ac and heat at the same time 88 201 - PeachParts Mercedes-Benz Forum

olpos · #1 05-31-2004, 12:23 PM

just hoping some one knows of a quick fix. i did the search but most have full heat/defrost and no ac.
i have both at the same time. lucky the ac over powers the heat.
my pbu may be bad as the temp dial does not change the temp.
just kind of strange to have ac/heat together. before i filled the ac ,turning the dial to full cold tured off the heat. now with ac the heat stays on. just hoping their is a vacuum some thing that may allow the heat /ac to work independently
only need a small miracle
rich

stevebfl · #2 05-31-2004, 12:30 PM

201 car has an on/off vacuum switched heater valve. The quick fix is to locate it in the cowl area and run a vacuum line to it. If you still have heat and the valve moves with vacuum then the gate in the valve is bad. The quick fix is a cork in the hose.

olpos · #3 05-31-2004, 06:00 PM

steve, thanks for the reply.so i just went out and checked it again. it worked last time and still works,but the vacuum signal is backwards.as i roll the temp dial i lose vacuum to hcv at cold and gain full vacuum at hot. may have the wrong heater control valve. with no vacuum the valve opens and there is full heat
some thing new to look at
thanks
rich

blairbuc · #4 06-02-2004, 09:39 PM

Olpos

my brother has a 92 300E,,,,I have a 90 300 E. This has happen to us and then goes away. Mine come out cool in the center and hot on the ducts going to the side windows.

On the few times it happens I shut the car off, turn on and its gone for weeks. Maybe hitting the 0 climate control of the pushbutton and then pressing another selection would do the same?

Not a solution, just a possible bandaid. I beleive you have a gate hanging up or binding from lack of use, but more opening and closing will one day stop it all together. So , if this happens mid season I would say the gate is sticky from being in heat mode for the winter. So it sticks in the early transition to summer and then goes away. If it happens mid season, then my guess is that it is close to being toast. My hope is that both our cars have a glitch and we just have to turn off and then on a few times as the summer starts to work the gate lose.

olpos · #5 06-03-2004, 01:28 AM

blairbuc,hi
hey i grew up in waterbury, ct. my family lives in chesire. i stay in shelton on river rd when i visit.
well i have the same problem with the side vents hot. i used my vacuum pump and pulled heat valve off. full vacuum. all vents work fine now. will keep looking for the answer
thank you
rich

blairbuc · #6 06-03-2004, 02:04 AM

Olpos,

Chesire, well when I was a kid I played hockey againt some school in Chesire, maybe it was Chesire Academy. They killed us.
I can't beleive you need AC up in that part of CT.

Anyway, you mentioned putting a vac on the line. I was hoping you just had a hang up from lack of use due to this being early in the cooling season. My guess is if you shut the valve on and off several times with a vac. and it's still happening then our cars are getting old or at least our gates.

How did you access the line to your gate, I have not tired this since my turn off- turn on sequence is buying me some time and false hope. Oh, I'm over near Stamford in the warm low land part of the state.

olpos · #7 06-04-2004, 10:15 AM

hey i grew up in ct. but now in the lowest part of california, san diego. it can be 80-85 any month of the year. no more ice storms.
on the 201 i have a vacuum operated heater valve under the hood. i took off the line to the valve,where i was taking my vacuum mearsurments, and applied vacuum with a mighty vac. left it there. now i have great ac,no heat. ac blows out of the correct places and very cold. it now blows cold from the side vents and defrost area.
thanks
rich