a/c +heat at same time?

mk1 · Post by **mk1** » Sat Oct 21, 2006 8:03 pm

Hi. Iam having a problem. When I turn my heat on, the a/c and heat come on at the same time. Heat comes out of the defroster vents and a/c comes out the other vents. I noticed heat was not coming out so I replaced the heater valve and finally noticed the heat was coming from the defroster vents. I flushed my radiator with the heat and a/c on when it tells me to put heat on. I noticed a few drips on my carpet on the pass side that must be from the heater core but doesn't look like antifreeze and don't smell like it either. Is the air/heat a vacuum issue? Thanks. Craig.

Post by **Briano1234** » Sat Oct 21, 2006 8:20 pm

Drips on the passengers side is from condensation from the a/c lines.

If no heat or a/c blows out the center vents, then ther eis a problem with the defroster servo that is located on the passengers side of the heater box, but is only available to replace buy removing the dash.

Drips on the drivers side is an indication of the heater core leaking.

If you don't have heat then check to see that your heater valve is adjusted correctly.

The side vents on the cabby only allow fresh air or a/c air to blow.

If your a/c select is in either the blue side or on the defroster, then only then does the a/c compressor engages.

for more information visit our loverly Kamz site.

http://www.cabbyinfo.com

mk1 · Post by **mk1** » Sat Oct 21, 2006 9:17 pm

hey. Thanks for the response. Good, its not the heater core leaking. I can't seem to get any air from the center vents. I just can't understand why the heat and a/c is coming on the same time. I have never heard any like this happening before. The vacuum lines seem to be good. I have been checking cabbyfacts and can't seem to find the heat/a/c problem.

kamzcab86 · Post by **kamzcab86** » Sat Oct 21, 2006 11:06 pm

Standard operation when hot air is selected in vent mode:
Heated air exits the center vent.
No air exits the defrost vents.
Outside (cool) air exits the side dash vents.*
Air conditioner (i.e. compressor) is off.

Standard operation when hot air is selected in heat mode:
Heated air exits the footwell vents.
Outside (cool) air exits the defrost vents and side dash vents.*
Air conditioner (i.e. compressor) is off.

In all other modes, the air conditioner is on (i.e. compressor cycles on and off).

*Unless the side vents are manually closed.

If no air ever exits the center vents, check the vacuum hose routing (the diagram has been updated to reflect the verified, correct routing), check for vacuum leaks in the HVAC system, check to see if the center vent vacuum servo is faulty (9 times out 10, this is the problem).

Post by **Briano1234** » Sat Oct 21, 2006 11:32 pm

take the hose off the divertor, and apply suction to it, if you can look down your center vents you should see the divertor move.

One cheap out, is to make a little hook outta a piece of wire hanger and use it to manually move the center vent.

Vw used plastic servo's for a while, and they also used a foam rubber as a return spring in them, this foam deteriorates, and causes the vacuum to stop.

On any wrecked car in the yard you will find that hte external fresh air / recirc vent in the rain tray is the same servo.. look for a metal one as they have a better shelf life. The Servo from the dealer is about 50 bucks.

mk1 · Post by **mk1** » Sun Oct 22, 2006 12:30 am

hey. what is the servo? Iam looking in my haynes and can't find it. Does this require taking the dash apart? If it does, I think iam going to take it to a shop . My aircooleds keep me busy enough

Is the rain tray that thin plastic sheet that is located under the hood by the windshield? Thanks. Craig.

Post by **Briano1234** » Sun Oct 22, 2006 1:29 am

Haynes? I just checked my haynes and there isn't a shot of it at all.

But if you take out your bezel and then look at the extreme right and a bit low you will see it.

And I can tell your from first ahnd experience you have to remove the dash to get to it.

gull · Post by **gull** » Sun Oct 22, 2006 7:57 pm

Before you start taking apart the dash, make sure the correct vacuum signal is being sent. There's a pin-and-cam arrangement on the selector lever that triggers the various modes. On my car it had popped loose, so I never got defrost or floor vents, only the center vents. If you pull out the radio you can see all the climate control levers and make sure everything is still hooked up.

mk1 · Post by **mk1** » Sun Oct 22, 2006 9:09 pm

Thanks, i'll take a look at that tomorrow.

kamzcab86 · Post by **kamzcab86** » Mon Oct 23, 2006 6:32 pm

Get a MityVac; remove the center vent hose from the distributor and hook it up to the MityVac; apply vacuum. If the servo retracts and opens the flap and keeps it open, the problem lies with the distributor or elsewhere in the vacuum system. If the servo does not hold vacuum and/or does not open the flap, the servo is shot. If the servo is shot, the dash must be removed to replace it.

Post by **kuklaki** » Mon Oct 23, 2006 8:58 pm

What, Kammy? None of those famous pics of you fixing the hvac?

(She's shy)

mk1 · Post by **mk1** » Mon Oct 23, 2006 10:25 pm

kanzcab, do you think that my a/c might just be stuck on when the blower comes on?

kamzcab86 · Post by **kamzcab86** » Mon Oct 23, 2006 11:10 pm

Well, maybe it's just me, but I'm rather lost as to what the problem actually is; every post seems to be asking about a different issue.

Let's tackle one issue at a time, the first being the no-air-out-of-center-vent problem (see my previous post).

If air is blowing out of all other vents (and it sounds like it is), there is no blower problem.

If you live in a cooler climate, when you turn the fan/blower on, OUTSIDE air blows out of the side dash vents, making it feel like the A/C is on (this is why some people modify the duct-work so that heat can blow out of the side vents; also, that's why the vents can be turned off). Put the selector lever on "vent" or "heat" and turn the fan/blower on. Does the A/C compressor engage? That is the key question. If the compressor does NOT engage on these two settings, there is no problem with your system. If the compressor DOES engage on these two settings, then, yes, you've got a slight electrical problem. Don't confuse the fan/blower with the compressor. The fan/blower (located essentially below the windshield, center) blows air into the car; the compressor (located below the alternator) robs the engine of a bit of power and it's painfully obvious when it turns on (and off for that matter

).

Cristine: I don't have any pics of me fixing the HVAC system (still need to rip the dash off to properly re-install the servo; so when I do that I'll snap a pic or two of me losing my patience

). I did have a "proper position for working under the dash" pic, but that pic is long gone.

mk1 · Post by **mk1** » Tue Oct 24, 2006 1:02 am

kamzcab86 wrote: Put the selector lever on "vent" or "heat" and turn the fan/blower on. Does the A/C compressor engage? That is the key question. If the compressor does NOT engage on these two settings, there is no problem with your system. If the compressor DOES engage on these two settings, then, yes, you've got a slight electrical problem.

sorry for the confusement

When I turn the vent or heat on the compressor automatically kicks on and the heat will blow out the 1 and 2 vents while the a/c is blowing out the side vents at the same time

Post by **kuklaki** » Tue Oct 24, 2006 2:07 am

mk1 wrote:
kamzcab86 wrote: Put the selector lever on "vent" or "heat" and turn the fan/blower on. Does the A/C compressor engage? That is the key question. If the compressor does NOT engage on these two settings, there is no problem with your system. If the compressor DOES engage on these two settings, then, yes, you've got a slight electrical problem.
sorry for the confusement When I turn the vent or heat on the compressor automatically kicks on and the heat will blow out the 1 and 2 vents while the a/c is blowing out the side vents at the same time

The side vents? Are you sure that it is not just cold fresh air coming out of those?