Heater will not turn on

volvo9485t · Post by **volvo9485t** » 27 Oct 2009, 22:33

94 Volvo 850 turbo

Problem: No heat, no defrost, no air conditioning is coming/blowing from the vents. The heater was initially blowing from the vents while warming up the car. Once I returned to the car, I noticed the heater had stopped working. No air was blowing or coming out of the vents. We replaced the blower, but the problem still exist. Please advise....Thanks in advance.

Novice

DeRail · Post by **DeRail** » 27 Oct 2009, 22:39

Is the blower motor running? If not, have you checked the fuse for the climate control system? I'm not sure which # it is but there should be a map on your fusebox cover.

-Darrell

Post by **polskamafia mjl** » 27 Oct 2009, 23:43

There's also a resistor or something that often breaks around the time the blower motor breaks down. Lee knows more about this than I do. The ECC confuses the *&%$ out of me.

Found this for you, may help. -> https://www.matthewsvolvosite.com/forums ... 22&start=0

Post by **Ozark Lee** » 28 Oct 2009, 19:18

Welcome to MVS,

First things first, is this an Electronic Climate Control (ECC) unit or a Manual Climate Control (MCC) unit?

They look very much the same but the ECC has "auto" settings and the temperature is graduated in degrees where as the MCC has fan speeds 0-4 and the temperature settings are marked with graduated width red bars.

I have worked on both versions but the steps to get there are very different.

...Lee

thepainted1 · Post by **thepainted1** » 30 Oct 2009, 07:58

Not trying to Hijack this thread, but I have a 1995 850 GLT Wagon with ECC and am having the same issue. Although mine used to work until this past spring when I tried to get the A/C working. The shop tested it and it passed and then recharged the A/C, then when they tried to turn it on, my whole Heater unit does not work, no lights on the A/C or cycle air.

Then last week, I got in the car and turned it on to find it was working, It worked for about 2 or 3 starts, and now is completely non-responsive again.

I am in Ontario, Canada, and the weather has been up and down these past few weeks, not sure if that has anything to do with it starting up again?

I didn't want to start a new thread since this one hasn't been answered yet, and hopefully we both can get our issues figured.

P.S. Also Ozark, I thank you in advance, as a lot of your posts have helped me previously!!

Post by **Ozark Lee** » 30 Oct 2009, 12:54

An ECC with no lights means that either the connections on the back of the controller are bad or the unit itself is bad. Since it seems to be intermittent I would start with the connectors on the back and give them a good spray with contact cleaner. The ECC controller is easy to pop out, just remove the radio (You will need your code if you unplug it) and reach up behind the ECC controller and push it out of the dash. The wiring harness is long enough that you can disconnect the connectors after it is out of the dash.

...Lee

thepainted1 · Post by **thepainted1** » 14 Nov 2009, 19:12

Ozark Lee wrote:An ECC with no lights means that either the connections on the back of the controller are bad or the unit itself is bad. Since it seems to be intermittent I would start with the connectors on the back and give them a good spray with contact cleaner. The ECC controller is easy to pop out, just remove the radio (You will need your code if you unplug it) and reach up behind the ECC controller and push it out of the dash. The wiring harness is long enough that you can disconnect the connectors after it is out of the dash.

...Lee

So cleaning and replacing it does not work. I don't think its the blower moter either as the control unit is unable to change the vents. I tried another unit, and it didn't do a thing. Where should I be looking next? it's like there is no power getting to it?!?!?!

Post by **confused_al** » 14 Nov 2009, 21:11

Have you tried pull your codes from port B-1? It should give you some idea what is going on.
Here is the ECC part from the service menu:

I'm sure once lee's back he will be able to help you more.

Post by **Ozark Lee** » 15 Nov 2009, 21:51

Codes are indeed the next step. If you cannot retrieve the codes remove the cover from the ECC controller and look for charred looking components on the PC board. The early model ECC units are burning up at an alarming rate.

...Lee

9394volvo850s · Post by **9394volvo850s** » 16 Nov 2009, 23:04

try replacing the resistor, worked for me.