Replaced Heater Core still NO HEAT!!
 

I have a 1992 volvo wagon 740 and I have not had any heat so I replace the thermostat and that was not it so I replaced the heater valve and that was not it either. So I took the plunge and I replace the heater core and I still don't have any heat. I think it might have to do with the vacuum lines and the dampener doors but I am unsure how to check, so if anyone could shed light onto this subject it would be greatly appreciated. THANKS

Well, it's a positive airflow system...so you should always be getting some air flow through the car. So...I guess your air just doesn't get any warmer? Do you have ACC or the standard slider heat adjustment? If the latter, perhaps the cable is either not attached or is misadjusted?

a '92 has the later system control panel which is probably bad... the circuit board inside

So if I were to replace the climate control module, which has the dial not the slider by the way, do you think this might fix my problem. Also is the circuit board inside the climate control housing. THANKS

It's all attached to the back side of the actual ACC panel you see on your dash...self contained. Good luck finding a used, working one...they're getting hard to find. If I were faced with a failed acc board, I think I would hunt down a schematic and see if it could be fixed.

depends on where you live, there are lots of them in wreck yards, they rarely go bad. i may have one.

Yeah, there's lots of 'em in JY's...but if they rarely go bad I wonder why LKQ sent 4 different units to the shop before one worked? Or the one in my 91T that was bad? LKQ sources parts nationwide...wouldn't think geography or climate would particularly affect longevity. Heck, they're 20 years old. I have a 2002 Explorer w/ similar stuff that didn't last 5 years.

well ok, rarely is a relative term but 4 out of 4 being bad, that's pretty bad odds, no? in my experience, they are pretty bulletproof as far as those kind of gadgets go... generally u don't hear too much about those things being a problem. and if u go the new route, i believe those things are like $700... btw, what does lkq get for them used?

Vacuum Works
 

Well like swiftjustice44 said I have positive airflow and I can change the direction were I want the air to go wether it be defrost on the lower vents or the high vents and I was wondering is this just hooked up to the vacuum lines and separate from ACC circuit board. Or in other words could the vacuum controlled dampener doors still change if the circuit board is bad. By the way when I change it to heat I do not hear any vacuum lines or and dampener doors opening or closing. Thanks