1994 Roadmaster wagon with DARK climate control panel ie no LED lights

[MrY]

I have a 94 Buick Roadmaster wagon and my CCP (climate control panel) goes dark
(ie no power to the display) and I can not turn on the defroster or AC or Heat
What could be the problem? how do I troubleshoot?

some days it works and some days not (of course it's not working when I need it the most ie defroster)
Sounds to me like there is a short somewhere
Where is the fuse or relay that powers the CCP ?

See pic when it's working - when not you don't see any GREEN and can not start or adjust the FAN / HEAT  / AC

[Frank DuVal]

The display on Park Avenues goes dark because resistors become loose on the circuit board. They can be resoldered to bring life back.

 

But, the control still worked, just could not tell what it was set at. So, maybe this problem on the Roadmaster is different? If you have no control, then power is lost. Fuses usually do not fix themselves, but loose connections do. Does lightly hitting the dash/controller get any response when it is dark? Do other car functions also stop working, like radio or?

[MrY]

Have not tried hitting the dash but it's worth a try,

Everything else electric in the car works and this only happens now and then all of a sudden while driving it comes alive

so there is some shortcut somewhere just trying to figure out where ... and what fuse or relay is giving power to the CCP

Driving me crazy ... in the summer I need AC and in the winter I need HEAT and this CCP controls it all (and many diagnostic codes etc)

thx

[NailheadBob]

Try reaching out to Bernie on this forum @60FlatTop he may be able to help you, he is the 91-96 Roadmaster tech advisor with the Buick club.

 

Bob

[NailheadBob]

You will need Roadmaster/Caprice 1994 GM service manual book 2 of 2,  electrical diagnosis starts on page 8A-63-0 and has flow charts, a library 30 minutes from me has a basement full of factory manuals to use, maybe your library has the same.

 

Bob

[MrY]

https://carmanualsclub.com/buick-roadmaster-owners-and-maintenance-manuals-pdf/

Fuse 17, 40 and 42 would be checked

 

 

[Frank DuVal]

Power all the time to the control panel is through fuse #33  10 Amp

 

Power "hot in run" that feeds  control panel is fuse #20   10 Amp

 

These are both in the instrument panel fuse box.

[NailheadBob]

Any update? Did you locate 1994 Roadmaster diagnostic manual 2 of 2.

 

Bob

[MrY]

Found out they closed down the library in my town so I have not found the pagers for 1994 Roadmaster diagnostic manual 2

I  been fiddling with the fuses that runs the AC/Heat on the fuse box panel and the relays in the engine compartment for the AC etc

but no luck in getting any sign of life in the Heater/AC/Fan control module - also been driving it around to hope it would just by chance start working again like it has in the past (like I said sometimes it comes to life and sometimes it's dead like now)

[MrY]

Found the manuals on Ebay ($80) .... but was hoping someone here would have the 1-2 pages I am looking for to share with me .....

[MrY]

isn't it ironic -- you can troubleshot the car via the Heater Control module --

(but mine does not light on or turn on so I am out of luck)

 

 

[Frank DuVal]

On 2/9/2023 at 10:51 PM, Frank DuVal said:

Power all the time to the control panel is through fuse #33  10 Amp

 

Power "hot in run" that feeds  control panel is fuse #20   10 Amp

 

These are both in the instrument panel fuse box.

Did you do this first check?

 

If the fuses are good, then pull the panel and see if the voltage appears there.

 

Fuse #33 feeds heater control terminal C12. Might be labeled BAT

 

Fuse #20 feeds heater control terminal C5. Might be labeled Ign

 

And check for ground  is good at terminal C1, might be labeled GROUND (At least this is what the diagram says)

[MrY]

Turns out I had to remove the dash and pull the Climate Control unit

and when I touched the wires on the back the light came on and AC and Heat and FAN

I put it back again and installed the dash again and then when I started the car again it was DEAD !!

 

So I pulled the dash again and once again the lights for the display came on while wiggle it in the back

I going to replace the CC unit with another one - I see they are for sale used and new on Ebay

I also tested the power to the wires in the back and they have power etc going into the CC unit

so there is something wrong with the motherboard / computer in the CC unit that sometimes work and sometimes dead.

 

I also got the Service Repair manual 3 of them which I bought from Ebay but I think I found the problem

 

 

[MrY]

https://youtu.be/U_-ECgi1_ag

 

how to remove a Roadmaster 94-96 dash instructions

[Frank DuVal]

Open it up, easy, and solder the loose connection. BTDT on several Park Avenue versions.

 

What if you screw it up? Well, you were going to order another anyway! This is the only way to learn. No downside.