Troubleshooting climate control unit

[jasonhi]

My climate control unit recently started only blowing air on the full-on setting.

From searching past postings it appears that on older cars it was often the power transistor and/or blower motor that failed. On others it sounds like it is the control box in the dash... some people replaced the capacitors on the board and/or sent it in to someone to do repair work on it.

I'm fairly sure that my blower motor works fine (it runs just fine on high), and the power transistor appears to be behaving correctly (no current can flow blue wire to black wire normally, but put a small voltage on the "small" (white?) wire and voltage can flow from blue to black (big wires)).

There is no smoking gun evidence in the control box of failure, but I can't come up with a good test to determine if it is broken or not. I don't mind replacing the caps in there if I know for sure the control unit isn't working, but I hate to ruin a good board (buy a new one) and then still have my problem.

Any ideas/suggestions for trouble shooting this more?

Anyone around Seattle have a spare they want to loan for a few minutes to see if my car works with it? (or have a dash that is open or don't mind opening to see if my unit exhibits the same problems in another car?)

Thanks!
...Jason
95 blk/blk
Kirkland, WA

 

[Ojas]

Since you have a 1995 model, I think the capacitors on the climate control board are the most likely culprit. My understanding is that failure of the power transistor and blower motor only occurs in 1991 and some 1992 models (the years to which TSB 92-007 apply).

There’s a pretty complete troubleshooting procedure in the service manual. In your case, I would start with the procedure on 22-40, but be sure to check the general troubleshooting chart on page 22-14.

You can probably find a local electronic shop that can replace all the capacitors on the board for $100 or less. Or, if you’re comfortable with soldering, you can spend a few dollars on the capacitors and do it yourself. If you can’t find a local shop, there are a number of shops mentioned in past threads, including Langguth Electronics Inc.

 

[hlweyl]

I agree with ojas, it's probably the board. It's not that hard of a DIY project to pop the board out and inspect it. Chances are a couple of the capacitors went bad, they tend to "bleed" out onto the board and contaminate the traces.

Same thing happened to my 97 and Langguth did the repair. Complete job, including shipping and extra insurance was $170.

Good luck

 

[pimp42]

Definitely pop the board out and inspect it yourself. If any of the caps are leaking, you'll see it.

m

 

[nsxtypet]

Dear members,

I had all 13 caps replaced for my climate control unit but it still remained in black out display, high wind speed, can't control anything when there is no display.

Do I really need a new unit since my TV repairman said that it would probably the CPU has gone!!

Suggestion is welcome!!!

Thanks

Tom

 

[hlweyl]

From what I remember when I did mine, there are 2 cpu boards in there. The one in the back is usually the culprit but in your case it sounds like it might be the front board that has gone.

And remember, all electronic shops are not created equal. My brother said he could solder some new capacitors on... I thought it would be better to send it to someone like Langguth Electronics who has successfully done them in the past. All soldering equipment are not created equal also!

Good luck