Attention All Heating Experts I NEED your assistance

[bklynsupraman]

I have been fighting with a no heat problem for a while now and I have finally gotten around to whipping out the multimeter and checking the resistance of the cabin temperature sensor and temp sensor by the condensor. They both ohm'd out less than posted resistances, 1.5 for the in car sensor and 0.3 for ambient temperature by condensor. I unplugged both to see if car would go into max heating but it did not. I am sure both sensors are going to need to be replaced but I am a little confused as to why the climate control system did not go into max heating when unplugged. If anyone could offer any theories or suggestions to help me along I would be greatly appreciative. Thank you in advance.

['82supra]

Is it possible the VSV (vacuum switching valve) on the firewall is faulty, or that the vacuum lines connected to it are reversed?

[Dean]

In case you haven`t read this already...

http://www3.sympatico.ca/dean.anders...tingSystem.htm

Info on the Mk2 heating system. Maybe it will help you troubleshoot.

[scottevil]

Have you check basics? Do you feel hot coolant going into the firewall? There is a hose that runs to the heater core. Could be clogged. Never really looked into the mkll system before but it Could also be a stuck blend door.

[bklynsupraman]

Hey didnt expect such quick responses. Vsv on the firewall worked when i checked it last. Here is a lttle further background, I initially brought it to my mechanic to have it fixed i rememver him telling my something about the cable for mixer door being problematic, it worked when i
got car back and then quit after one day. I will say that when i tried pushing rod for blender door it almost felt stuck but i am not sure how hard it should be to push though i think maybe i will take apart again and attempt to troubleshoot some more.

[scottevil]

If it felt stuck then it probably is. The door should fucntion smoothly. If left open then all you're Gunnaa get is cool or cold air.

[zuprax85]

cable for the blend door???? our cars dont have a cable for that, they used that vacuum pump, i cant remember the name of it....do you hear any clicking while setting the temp to max cold and max heat????? pull the woofer panel at the passenger side, and make sure the orange connectors are tight, had a similar problem before and ended up being a corroded plug.

[bklynsupraman]

Well I am pretty sure I have sorted out what the issue is. I pulled radio to give it a second look and felt around the servo unit and noticed there was a loose rod with a threaded end behind it. I am guessing it attaches to servo unit, I pulled on rod and turned car on and in came the heat. It got late pretty early today so I will pull servo unit tomorrow and see how rod attaches to it. I am stoked to get some heat in my car. Thanks for the reply's I will post back results after I work on it tomorrow.

[bklynsupraman]

I played with heating setup some more, connected rod to servo unit and still no heat. With rod attached to servo unit I unplugged sensor by condensor and still no heat, I play with check connector (blue plug) and watched rod movement, there was none so no vacuum leak, I checked plug under dash, orange with orange, orange with white, orange with red and orange back to orange and the only thing I heard was an electrical pop, maybe relay or something clicking when the plugs would make contact. Still no heat, there is no heater core blockage as both hoses are hot and when I pull rod that attaches to servo unit that opens door I get toasty heat. There is clicking when moving temp lever from max heat to max cold Edgar. I have done every check possible and am stumped, could problem be servo unit itself? Or maybe climate control computer? Any help would be greatly appreciated.

[bklynsupraman]

Pretty sure I have got this one figured out but it is raining so cannot say for sure. In addition to rod for door not being in its place, which I have remedied, it seems when I swapped y pipe on 2j and reconnected vacuum line I mixed two up and though it is corrected now, there is a line missing from vacuum tank that come from engine. When it stops raining i will hook that up and give the heat another test.