How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Roy Your Own Question
Roy
Roy, import/domestic specialest
Category: Car
Satisfied Customers: 4638
Experience:  ASE master tech for 40 years
3506196
Type Your Car Question Here...
Roy is online now
A new question is answered every 9 seconds

I have a 1990 gmc 2500 that has the A/C flashing in control

This answer was rated:

I have a 1990 gmc 2500 that has the A/C flashing in control panel, it is affecting the air conditioning to the point it just won't work.
Good morning my name is XXXXX XXXXX I will try to assist you today.

I found a TSB from GM on this issue I will show you about the contacts on the control head. I would check this first. Did you check the pressures??

Group Ref.: HVAC

Bulletin No.: 461202

Date: May, 1994

SUBJECT:
A/C CONTROL HEAD FLASHES OR ERRATIC OPERATION OF A/C CONTROLS (POLISH TERMINALS)
MODELS:
1988-94 CHEVROLET AND GMC TRUCK C/K MODELS
1990-94 CHEVROLET AND GMC TRUCK TOPKICK/KODIAK MODELS WITH C60 OR C69 AIR CONDITIONING
CONDITION:

A/C Control Head flashes, performs erratically or malfunctions.

CAUSE:

Light surface corrosion on the Control Head terminals.

CORRECTION:

Remove the A/C Control Head and while holding the unit with the terminal cavity down (toward the floor) so no particles will fall inside on the circuit boards, polish the terminals on both sides of the cavity with a lead pencil pink eraser. Do not use an ink eraser or other abrasive such as a small wire brush or sandpaper, etc. Doing so will remove the terminal coating and degrade the contact surface.

Performing this procedure, in many cases, will make replacing the Control Head unnecessary. Using this procedure in conjunction with the A/C circuit diagnosis found in the Electrical Diagnosis Manual and especially before replacing a Control Head for any reason is recommended.

After polishing the Control Head terminals, but before reconnecting, check for proper terminal contact as described in the applicable electrical diagnosis manual. If contact is good, apply dielectric grease (P/N 12345579) to the harness connector terminals. Please do not apply grease to the Control Head.

SERVICE PARTS INFORMATION:

P/N Description QTY
12345579 Dielectric From Tube as
Grease Needed
Parts are currently available from GMSPO.

WARRANTY INFORMATION:

For vehicles repaired under warranty, use:

Labor Description Labor Time
Operation
D0362 A/C CONTROL Use Published
ASSEMBLY Labor Operation
Replace Time

Roy
Roy and 7 other Car Specialists are ready to help you
Customer: replied 3 years ago.

After doing said rpr truck still flashed A/C in control panel, can u buy a new or reconditioned control head?

You would have to check the dealer but I doubt it. A parts store usually has access to having your unit re built on the outside. You would remove your unit and send it away. It takes about a week or so to have this service done.

 

Roy

Roy and 7 other Car Specialists are ready to help you