A/C Control Head - Flashes, Operates Erratically

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