Climate control questions

hello all,

My car had the usual intermittant heat gripe when i got it, so I replaced the monovalve. Then it only blew insanely hot air any time the climate control was on, regardless of temp wheel position. So i ripped the glove box out and replaced the air temp sensor hose (which was bad). now it only blows hot air, regardless of wheel position. I verified my servo's operating correctly for the various modes (defrost, EC, etc.) so it's not leaking vacuum. The things i think it might be are:

1- bad temp sensor? how do i verify this? my thought was to take it out and blow hot air on it and see if the ohms change with a meter.

2- no signal getting to monovalve? how can I verify that the temp wheel is changing the signal to the monovalve? would reading out the volts at the monovalve plug with a meter while changing the temp wheel work?

3- bad temp wheel? this should vary ohms according to switch position correct?


again, this forum is a valueable tool and I thank you for your time guys!

[Fisherman]

This always helps in trouble shooting. To check the various outputs of sensors etc in the car there is a ten pin plug tucked away (on mine it is against the firewall on the passeneger's side behind the blower motor.
Knowing the year and model it is possible to pull the spec for the electrical test adn you can check these parts through pin combos in this plug, i.e. temp wheel is holes 8 and 5 with a resistance reading of X at 65 degrees and X at 75 degress set on the wheel.

Do you have the CD for your car? Pretty cheap on ebay and it provides all the specifics for checking this stuff.

it's an 83 300d, maybe i should get the cd for this thing. where is that plug at exactly?

[Fisherman]

without the CD I can guarantee it will only look like a plug as you will have no specs to check.

The description above is really the best i can offer on this for location and this is in my 80, I think your car may be different and how much I do not know.