Climate Control Unit Repair

[curator]

Having just successfully repaired my 94's climate control circuit board I thought I might post and let others know what I encountered.
My problem was lack of blower fan speed control as it would only run on high when the blower high relay was on, otherwise the blower fan would not run.
Upon initial board inspection I noticed capacitors #44(22micro farad/35v) and #32(47micro farad/50v) had leaked black goo onto the board. Capacitance testing gave me a reading 1.87micro for #44 and open for #32.
I decided to replace them one at a time and see if one made things work. Replaced #44 first and blower would not run unless high (still the same) then after replacing #32 it works again.
If I was doing it again when I had the caps off the board I would pay really close attention to the condition of the board's traces that lead away from the positive side of the caps and pre tin the pads and check for continuity of the traces before inserting and soldering in the new caps then check again to make sure every thing is good. This black goo is corrosive and either ate the positive trace on cap #44 or I was not getting it clean enough to solder and resorted to putting a jumper in between #44's pos leg and the through hole solder just below the writing "Q20" ( just replaced the trace). Hope this helps, Mike

 

[Briank]

Nice Job. :wink:

 

[Fireballs_92nsx]

"My problem was lack of blower fan speed control as it would only run on high when the blower high relay was on, otherwise the blower fan would not run."

Mine doesn't run on high? It doesn't run at all. I can put it on the mode that sucks air into the cabin from outside, but it comes in with no pressure at all. Is this something that prob has to do with my unit? Every button works, and I have searched and changed fuses that need to be changed, I need to send the unit off to brian when he offers a sale again.

 

[Briank]

It's uncommon for the climate control unit to not run the fan at all. First thing I would do would be to hot wire the blower motor and see if it runs. Next check the blower high relay.

 

[Fireballs_92nsx]

Where is the blower high relay?

Also, I replaced the entire blower motor with a used but working unit, and I have a spare one in my garage. Silly question, but how can I run a hot to it and see if it works, also can I do this while it is hooked up on my car. Neither blower motor did anything for me. The ccu unit make all the noises, movements, and all functions work except the fan speed.

 

[chippy]

Mine blows fine, but its not really cold air that comes out..atleast not as cold as i've experienced in newer cars. Thoughts?

 

[Briank]

Low on freon would be my first guess, next would be that water valve is misadjusted, and then a problem with the Climate Control unit.

 

[Fireballs_92nsx]

Where is the blower high relay?

Also, I replaced the entire blower motor with a used but working unit, and I have a spare one in my garage. Silly question, but how can I run a hot to it and see if it works, also can I do this while it is hooked up on my car. Neither blower motor did anything for me. The ccu unit make all the noises, movements, and all functions work except the fan speed.

Briank, I checked my relays, and they seemed ok, I am hearing a clicking noise under the hood when I am turning the knob for the fan speed. It seems like it is wanting to work, and I am still getting all the proper buttons to work except the fan speed button.

 

[Briank]

Briank, I checked my relays, and they seemed ok, I am hearing a clicking noise under the hood when I am turning the knob for the fan speed. It seems like it is wanting to work, and I am still getting all the proper buttons to work except the fan speed button.

The fan hi relay closes when you go to max fan speed or min or max temp. If you can her it operating at those times the fan should be runing full speed.
I assume you pluged in all the connectors when you replaced the blower assy. The 2 pin middle one of the 3 is the blower motor, which you can unplug and apply battery power to the male pins to confirm the blower motor it OK.

 

[Fireballs_92nsx]

Hey Briank, I hooked up a power source to my motor and it works. So, the problem has to be in the relay, the relay box, or the head unit. One of the relays has a buildup in between the two metal prongs, so this could be some type of melting. Let me know some more thoughts. thanks

Fixed the problem!!!!!!! It was one of the two relays that are identical. I need to replace one and I am ready to rock and roll. Briank, thanks for all your help, along with everyone else.

 

[lithiumus]

Hey, what do you use to clean the capacitor acid off the circuit board or did you just leave it?

 

[Hugh]

Hey, what do you use to clean the capacitor acid off the circuit board or did you just leave it?

Here ya go!

 

[Briank]

Here ya go!

Oh OK :tongue:

 

[lithiumus]

Here ya go!

Cheeky! :tongue:

I should not have generalized the question so much... Some circuit board cleaners are good for washing the acid when etching the board and some are good for prepping the oxidized copper when tracing...

I was hoping that someone (briank) would chime in on any experience with specific chemicals that are excellent for removing capacitor acid...

 

[chippy]

Low on freon would be my first guess, next would be that water valve is misadjusted, and then a problem with the Climate Control unit.

If the freon is gone, i guess there must be a leak? Since the AC system is a closed system. Couldnt find any FAQ on how to replace this, guess it must be done at a repairshop?

 

[Briank]

Yes its a shop repair to evac and recharge.

 

[Briank]

I was hoping that someone (briank) would chime in on any experience with specific chemicals that are excellent for removing capacitor acid...

Sorry but you will have to contact me in private and pay a large consulting fee. :wink:

 

[sers]

My fan runs only on high for the first 5 minutes, then after that it runs on all speeds. Weird.

Any thoughts?

 

[Briank]

My fan runs only on high for the first 5 minutes, then after that it runs on all speeds. Weird.

Any thoughts?

I would expect it to get worse as time goes on. See if you can make it through the summer and then send it to me for a rebuild.

 

[curator]

My fan runs only on high for the first 5 minutes, then after that it runs on all speeds. Weird.

Any thoughts?

You have described the behavior that I was experiencing last summer. It became worse until finally it would only run on high.

 

[passline]

My CCU works fine on all functions but there is no display and I am unable to know what mode it is in until I go through each one until I hit it.

Any ideas?

 

[Briank]

My CCU works fine on all functions but there is no display and I am unable to know what mode it is in until I go through each one until I hit it.

Any ideas?

That is problem I see on some units.

It needs repair, PM me or Email [email protected].

 

[emdoller]

Having just successfully repaired my 94's climate control circuit board I thought I might post and let others know what I encountered.
My problem was lack of blower fan speed control as it would only run on high when the blower high relay was on, otherwise the blower fan would not run.
Upon initial board inspection I noticed capacitors #44(22micro farad/35v) and #32(47micro farad/50v) had leaked black goo onto the board. Capacitance testing gave me a reading 1.87micro for #44 and open for #32.
I decided to replace them one at a time and see if one made things work. Replaced #44 first and blower would not run unless high (still the same) then after replacing #32 it works again.
If I was doing it again when I had the caps off the board I would pay really close attention to the condition of the board's traces that lead away from the positive side of the caps and pre tin the pads and check for continuity of the traces before inserting and soldering in the new caps then check again to make sure every thing is good. This black goo is corrosive and either ate the positive trace on cap #44 or I was not getting it clean enough to solder and resorted to putting a jumper in between #44's pos leg and the through hole solder just below the writing "Q20" ( just replaced the trace). Hope this helps, Mike

Mine had the exact same problem and I thought I'd give it a shot before sending it to BrianK for repair.

I removed both caps (#44 and #32 ) as they had leaked. I soldered in new ones and also had to run the jumper from the positive lead of #44. As I said, exactly the same. I checked for continuity between the leads and the pin connectors on the back to see if they were indeed hooked up and everything seemed ok. I was not getting this in the positive lead of #44 which is why I ran the jumper like stated above.

When I hooked the unit back up, it did not fix the problem. It was doing the same thing it did prior to me swapping out the capacitors.

So, I have 2 questions:

1) When I removed my caps, I neglected to write down which cap went where and used the information above (22uf in #44 and 47uf in #32). Is this right?

2) Is there anything else I can check before I send it to BriankK?

Thanks for you help!!

Ed

 

[Briank]

#44, 22 X 35 and #32, 47 X 50

 

[mastaf]

My A/C had been behaving temperemental lately. Sometimes blowing cold air, sometimes blowing hot. Having CCU repaired by Brian a few years ago, I didn't think CCU would be the problem. My mechanic told me the there was no leaking of R12, however the compressor wouldn't engage, because the gap was more than twice what it's suppossed to be (almost 2 mm). That was adjusted, then another small problem; there is another small board just behind the seats that acted strange. When you tap it it works and then stops. Some soldering were done to make sure all circuitry works. A/C works fine now.:smile: