A/C performance problems -- not compressor/freon/evaporator related


New member
I've had this problem since I got the van 3 yrs ago: The engine won't idle with the A/C on. Not such a big deal, but quite annoying nonetheless. I have an '85 Westy with manual transmission. The A/C is a retrofit done by a company in California 9 yrs ago (previous owner). Can't seem to find anything in Bentley's to help. Does anyone know whether the idle bump is supposed to be accomplished mechanically or electronically? I'm guessing the system installed would be similar to a factory instl.
Tim Wilson

[ 06-28-2001: Message edited by: Capt. Mike ]

Capt. Mike

Obviously without the wiring diagram for an aftermarket A/C, anything here would be a guess.

Did you do any preliminary checking of other sources such as the idle transfer switch adjustment?

If you look at the wiring diagram for an OE A/C on page 97.138 in the Bentley, you will see an Idle Speed Stabilizer Valve connected to the A/C compressor cut-out relay and in parallel to the A/C compressor clutch. It's purpose is to ground (activiate the cut-out relay) when the idle is not stable, thus cutting out the A/C compressor clutch (& compressor). Thus the A/C is not operating when the engine is having idle problems.

You would have to trace this aftermarket rig wiring to find out how it handles that problem.

To answer your question, according to the OE wiring diagram, the symbol for the switch indicates it is electrically operated (Bentley guide page 97.5).


New member
I own an '85 Westy with A/C, and how my system works for idle increase has to do with a vacuum switch. When the A/C is turned on, the vacuum switch opens and allows more vacuum air after the Air Flow Meter, which increases the amount of air flowing thru it - which then makes the sensor plate open slightly more and ups the fuel for increase in idle. Its works like a step modulator - look and see if you have a vacuum pot - a square looking thing with two vacuum hose on it, one on each end, with two wires going to it. It maybe that your switch is bad and not opening up with A/C on. Hope this helps and good luck. CGOTTS


New member
Thanks to both of you for the hints. I haven't yet looked more closely at the system--the weather's starting to get nastier here and my van lives outdoors... I need a good weekend to do some maintenance.

I'll report my findings here when I get around to further investigation.

Capt. Mike

Transferred from other posts to consolidate similar topics.

AC inadequately cools '85 Westie

bailey711 Junior Member # 34 posted 05-23-2000 06:25 PM

Last summer I noticed my rear-mounted AC in the '85 Westie had difficulty cooling me - in the front seat. NC had a brutally hot summer last year, and I was warmer than I wanted to be most of the time!

I've just gotten more freon and the dye the mechanic used should pinpoint any leaks, but I'm still worried about driving in the Southwestern desert this summer. Are there any tricks for getting the cool air to the front of the van?

I know one of the problems is that the cool air has a lot of hot air to replace in a large van. Would it help to plug up any gaps between the pop top and the roof with towels? Is it legal to drive with the side curtains closed?

Any suggestions would be appreciated.

Thank you very much.


Capt. Mike Moderator Member # 11 posted 05-23-2000 07:23 PM

The A/C on the Westy has several obstacles to overcome, size and insulation are just part of it. The roof opening and air leaks are not the biggest problems. Assuming your system is working fully, the battle is not the amount of cool, but the circulation.

Start by closing off the two downward facing vents -- they syphon off from the front. Back seat passengers will get plenty of cool w/o them. Second, read the post on the TIPS board about the Vanagon heat & ventilation controls. It's possible you are not getting all outside air shut off. (Top 2 levers left; bottom 2 right; both front dash vents closed!) This leaves the remaining A/C aimed at the front cabin. Be sure you have no hanging obstruction like towels and stuff from the pop-top roof rack; it's a tempting place to hang things, but blocks air to the front. Finally, consider putting in a couple of fans on the front dash. You will find the A/C tries to circulate BEHIND the front seats -- path of least resistance -- since it is being drawn back in above the rear cargo area. Getting 'over the wall' of the front seats is the problem. I've got 2 Hella rotary fans, "Model Rotor 12v w/ switch P/N 87170". Size is 5.75” L x 2” D x 4” W. These have variable speed switches and can be rotated to almost any position. Mine are left & right near the windshield. There is a picture posted on my pic-post site (access from Home Page) under Westy Accessories, "Front Cabin Accessories." By angling them slightly sideways, you create a circular movement in the front cabin which allows the A/C to penetrate.

bailey711 Junior Member # 34 posted 05-24-2000 04:38 PM

Captain Mike,

Thank you so much for your suggestions. I have printed your advice, including the info. in the "tips" section, and will implement all your ideas.

I'm unclear on just one point. You said, "Start by closing off the two downward facing vents - they syphon off from the front." Are you referring to the middle AC vents in the back, or some other vents I don't know about? It seems to me the AC has only two round portals on either side of the slatted middle vents. Closing the middle vents would, I would think, prevent the cool air from getting out. But, then, I'll do whatever you say - as long as I know what it is!!

Thanks again,


Capt. Mike Moderator Member # 11 posted 05-26-2000 12:35 PM

The A/C evaporator (cooling coil & blower) on the Vanagon Westy is all in the overhead cabinet over the rear seats. There should be 4 slotted vents that face directly forward towards the front cabin, and two more that face downward directly over the rear seat passengers. Close off these two vents as best possible which will force more air out out the front-facing units toward the front seats.

Addendum 6-7-00: Some older Westies have only forward facing vents, mixed rectangular & round. Although closing off any vents increases air flow out of the remaining ones, too much restriction would put strain on the blower. Therefore I would not attempt to close off the forward facing vents.

Non-Westy Vanagons have a roof channel that carries air to the front cabin but the Westy roof opening kills that option.

Again, do read the Vanagon heat & air control topic on the TIPS archives to be sure you're not confusing any fresh air vents with A/C air. There is NO A/C coming out the front dash vents or the vents in the channel over the sliding door. That's why it's critical those vents also be closed off.

There are two speaker ports (round) in the lower section of the A/C cabinet for the factory 4-speaker kit if so equipped but they are not part of the A/C.

tonynbarb Member # 681 posted 03-25-2001 11:43 PM

I dont think the air conditioner in our 87 Westy has ever worked adequately. I can't imagine owning one someplace hot like Las Vegas. When we went to Las Vegas probably around 1995 was the last time we used it. Prior to the trip the VW shop charged the system and it cost us about $120. It barely worked adequately enough to keep us alive. After the trip we didn't bother with any more as it didnt seem like it was worth the trouble to try and cool the van with it. Luckily we live in San Diego and can get by without it.

Several years later when I was changing out the fan belts I decided to leave out the belt for the air conditioner as I figured we don't use it anyways. I couple of years after that a strange problem occured. When I came to a stop the engine would start racing big time. You could smell the clutch burning as it was racing that high. I went to several shops, but they were too busy at the time. I stopped at this one place and the mechanic wanted to look inside the engine compartment. As soon as he looked in he knew what the problem was. Apparently the air conditioner switch on the dash had been accidently turned on and giving the engine extra power to operate the compressor. And since there was no belt the engine was racing. Any ways the problem was solved by turning the switch off.

Capt. Mike Moderator Member # 11 posted 03-26-2001 08:02 PM

That's an interesting observations and one few would give thought to. The FI system DOES have an A/C sensor to compensate the idle when the A/C is on.

I'm sorry you're having trouble with the A/C and I do hope you'll at least determine if it's your system or your expectations.

The A/C in a Westy is badly handicapped by the fact it doesn't have ductwork to the front passengers. Elsewhere on the site you'll see some various tips for improving circulation, but I'll be the first to admit it's less than ideal. However, first measure your temperature output. The A/C is quite capable, if operating properly, of putting out 55°F air. This will usually freeze the rear seat passengers, even if the front is hot. This is because the cold air naturally sinks to the floor and is drawn back to the A/C intake in the cargo area overhead. The air moves in a beautiful, efficient circle -- that never gets past the front seatbacks!

So do check you system output, pressures and temperatures. If working properly, you'll still get much use out of it.

V. Threlkeld

New member
1988 Westy: Problem - Debris from the A/C Vents (I'm not sure if this should be a "New Topic" or "Reply" -- but you can set me straight on that, also.)

Just had the A/C system recharged, switching to R-134a, after a year of non-use, easy to do in Seattle. By the the time I got home, using A/C all the way, the car was littered with fragments of a black, rubbery, sponge-like material of very low density. I removed the plastic vents (8 of them) and vacuumed out as much material as possible. But, I've run it again two or three time and the supply is NOT exhausted, whatever the source (at least the air remains cold!). I've talked to 3 mechanics; one thinks it could be dried out padding material used to prevent excessive component movement. (Naturally, all this happens just before a long planned trip.)

Any other suggestions, as to where the material is located, and can it be replaced or removed (especially by a non-specialist)? My Bentley seem quite vague when it come to removing the evaporator housing in the Westfalia. Thanks for any suggestions.

Capt. Mike

The evaporator section of the A/C has insulation inside that has deteriorated and is coming apart. Sorry there is no cure except to keep vacuuming -- and maybe add some small hose to reach deeper in (but not damaging the squirrel cage blower as that is expensive). If you blow through with compressed air, do keep pressure very low <30 psi) so you don't damage anything.

The long term repair is to pull the evaporator and reinsulate. I'd try to hold off until a system failure has the system open anyway. The main purpose of the inslulation is to prevent condensation so watch your roof panel for any sign of wetness or stain in case it doesn't drop into the drip pan.


New member
I solved this (circulation) problem in my 85 Westy by purchasing a clip-on 12 volt fan at Wal Mart that plugs into the lighter socket. It swivels and has two speeds for optimum airflow. I clip it on ceiling behind the passenger seat. It does a wonderful job of helping the cold air reach the cabin.

[ 03-07-2002: Message edited by: Capt. Mike ]


New member
I have a 90 Westy with dead air conditiong.

I've gone through the Bentley wiring diagrams to try to diagnose why my A/C has died. When I turn the A/C switch nothing happens except the rad fan starts up.

No blower fans spring to life, no comressor action. Nothing. I've checked every fuse in the system, even the big 50amp. I have given the A/C relay a tap to see if its sticky. Nothing.

Any suggestions out there?

Laurence Smith


New member
Laurence, You might check to see if the freon level is ok. If the freon is low the compressor will not turn on. Just a thought.

Tim Hannink

New member
<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by V. Threlkeld:
My Bentley seem quite vague when it come to removing the evaporator housing in the Westfalia. Thanks for any suggestions.<HR></BLOCKQUOTE>

This is how I lower the evaporator cover on my 1987 Vanagon Camper.
Remove the duct housing (with the vents) above the rear seat. I use a razor blad and a small screwdriver to pry the covers off of the screws. Remember the four Phillips screws that hold it in from the upper bunk. I ususally do those first so I don't forget them.
Remove the two Phillips head screws on the front of the evaporator cover.
Remove the rearmost bolt holding the evaporator cover to the rear cabinet.
Remove the rear grill cover.
Remove the front bolt holding the evaporator cover to the rear cabinet.
Disconnect the drain hoses from the drip pan and pull them out of the holes in the evaporator cover.
Support the bottom of the evaporator cover. (I use a large hydraulic jack with a laundry basket on top of it.)
Remove the two Phillips screws on the bottom of the evaporator cover.
Lower the cover 4-6".
Disconnect the wiring to the blower motors and the speakers. (remember to fish the speaker wire out of the cover)
Unbolt the blower resistors from the evaporator cover.
Lower the evaporator cover and remove it from the van. (the cover weighs about 20 lbs)
Remove the inner housing and deflector from the front of the evaporator, it should pull straight out from the front.
You should be able to see whats left of the old foam weatherstriping now on the inside of the outer cover.
I used 1-1/2"w x 1/4"d foam weatherstripping used to seal bed toppers to the back of pickup trucks as a replacement for the original foam.
You also need to pay special attention to where the A/C pressure hoses and evaporator drain hoses enter the inner housing. I wrapped layers of the same foam around the hoses in order to build them up enough to seal the gaps.
I took the time to clean and oil the blower fans as well. This is also a great time to upgrade your rear speakers.
Re-installation is, of course, the reverse of removal. I used a stainless duct tape to seal the rear sides of the inner housing to the brackets that the bottom of the outer housing screw into.
Before I re-installed the duct housing, I put in some foam rubber channels inside it to divert all of the air to the front vents. A photo is here: http://home.earthlink.net/~tjhannink/photos/Additional_Air_Channels2.jpg

The foam came from Walmart and is part of a window A/C insulation kit. I glued it to the cover with 3M spray adhesive.

I also have a post in the "Demystifying Vanagon heater & fresh air controls" which has more info about improving the performance of the Vanagon Camper air conditioning system.

BTW, the best tool to have when doing this is a fully charged cordless screwdriver with a good #2 Phillips bit.

Good luck,

Tim Hannink
Goldibox - 1987 Vanagon Camper, Wolfsburg Edition
Winter Park, Florida
http://photos.yahoo.com/tjhannink Vanagon Album

Capt. Mike

Transferred to consolidate same topic.

Dru Junior Member posted June 25, 2004 07:49 PM

I recently moved to Tucson, AZ, and had my '85 Westfalia's A/C compressor, receiver and dryer replaced at Beaudry VW Dealership. The problem is that the "parked" temp inside the van can reach 114 and then my A/C has difficulty cooling such a huge space.
If I put up a barrier (cardboard or plywood) right under the rear vents right behind the back bench seat to block air from moving into the far back area, would that interfere with the A/C's functioning? I thought maybe minimizing the amount of space that has to be cooled might help. On the other hand, I know the far back upper vent (where there's a shelf)can never be blocked and I don't know if that vent has anything to do with the A/C functioning.

Any advice would be very much appreciated.


Capt. Mike

Such a 'block off' would be self-defeating. That grill above the rear shelf is the evaporator intake. All air coming out the vents must first go in there. Although I don't doubt there might be enough leakage around a curtain to allow the A/C to continue to work, it will add temps to the evaporator and thus higher compressor pressures and work-load.

The Vanagon A/C is, for all practical purposes, an aftermarket design, so it is a recirculating system. It takes inside air and conditions it. Thus, over time, the air is cooler and dried, so the A/C works less and is more efficient as compared to taking in fresh hot outside air and attempting to bring it down to that level. But . . .

The problem with the Vanagon A/C is circulation, not capacity. You're on the right track, but the ideal would be to somehow get vents into the front cabin and not have it recirculating the cabin air behind the front seats. Elsewhere you'll see suggestions of front cabin fans to assist circulation. The non-Westy vans had ductwork carrying air to the front cabin, but that isn't practical with the poptop roof opening. Blocking off the cargo area by putting a tarp or cover over the cargo at or even above rear seatback height could reduce interior A/C volume. Since cold air sinks, ditto the entire camping cabin-space. But you still run into the problem of the cooled air reaching the front cabin.

I'm still convinced that some sort of ducting, perhaps removeable or tracking along the sides of the roof opening that exited in the front cabin would solve most of the problems. I just haven't had enough 'round-to-it' to design and fabricate one. I just finished a beach trip with kids and they were freezing in the back while we roasted in front, even with dash fans.

So I'll continue to look for some way to duct A/C to the front cabin. With the new collapsable ductwork now availalbe, maybe even something that snap fastens to the rear panel, fan assisted. Lousy design. The Type II's had the evaporator under the dash and was the way to go. It reduced rear A/C but not to the extent the rear evaporator does to the front. The driver/passenger seat are almost always used -- the rear seat far less so.


New member
I have a 1984 California Westy with a dealer installed Behr system (blows from the front with the fan and cooling switches).

I thought it needed coolant, but it mysteriously started working about a month ago. It blew ice cold and kicked the idle dowbit. It then started working intermitantly, and now it's not working again. The compressor's not engaging. I'm suspecting an electrical problem. Does anyone know where I can find a wiring diagram of this system? I checked the switches wih a multimeter, and they seem good. Any other suggestions?


Capt. Mike

Get a set of gauges on it. What I suspect, since it will blew very cold before cutting out, is you've got an overcharge and the high-pressure switch is cutting out the compressor. Other possibilities are icing -- if it starts cool and then quits, which will have the same effect on pressures. Failure of the evaporator fans will do the same.

"A/C Diagnostics . . ." has its own topic this forum.

The Behr was similar to most aftermarket systems so the wiring diagram for late Type II's posted on this site (Tech Drawings) should give you a good idea of what to expect. A good A/C manual like Murray Gold Seal's will show you how to test components. I have a Behr wiring diagram for a Porsche and except for that model not having condensor fans, it is very similar. Being dealer installed, you will at least have separate and easier-to-trace harnesses since they won't be part of the Vanagon OE sets.


New member
experience with A/C thermostat failure?

These threads on A/C have been very helpful; thanks so much Capt. Mike and co.

The A/C on my 1990 Vanagon GL camper was not working when I bought it last October. Now I'm trying to get to the bottom of the problem.

There has obviously been a minor burn in the D pillar, which probably explains why the previous owner turned it off and never tried it again, nor did he look into the problem. The evidence suggests that some wires/insulation got too close to the S-0 50aFuse (as warned by Capt. Mike elsewhere; see Bentley p. 87.4, photo 87-885)

The local Vanagon electrical expert converted the system to R134a, checked out all the wiring and found that the bad link in the system was the A/C thermostat - that is, when he bypassed the thermostat, the system worked, but otherwise would not. Does this sound a reasonable diagnosis?

...and, of course, any comments on experience with A/C thermostat failures would be helpful. The fact that I haven't seen any mention of this particular problem here has me concerned that it might be something else.
Last edited by a moderator:


New member
Hello all...new to this so please bare with me...Im looking for a little help with my 87 Vanagon. A/c is working finally after a new compresssor and converting to 134a. However even before conversion my fan seems to stop intermittent. It works great until I crank it up to 4 (and only on 4, 1-3 are fine and can run no problem for long periods of time...but as we all know 4 is what is needed to cool down the beast.) I can actually run it on 4 (full power anywhere from 10 to 20 min then something in the relays located behind the left pillar in the rear starts to click. And the blower starts to cut in and out. Fif anyone can help or point me in the right direction it would be greatly appreciated.


New member
clicking in the D pillar?

Hi ferchdogg,
Welcome! I assume you've opened up the D pillar (rear left) and run the A/C on 4 until the clicking starts. Step one would be to try to locate the precise source of the clicking - might be one of the relays A, B, or C (see picture on p. 87.5 of the Bentley manual) or thermostat (p. 87.6). I'm leaving my beast with a guy today to see if he can solve my ongoing problem (see earlier) - will ask him about yours for you. - Liam
Last edited:


New member
Wow! Thanks...look forward to his answer. Yes I took apart the pillar and located the clicking noise coming from the center relay from what I can tell. So I did the dumb thing and pulled some used ones from a junkyard Vanagon but it still made the same noise. Anyhow looking forward to your guys response...