Alternator trouble

Asked by Jan 27, 2017 at 08:53 PM about the 1985 GMC C/K 10

Question type: Maintenance & Repair

I have a 85 gmc and I've tested the alternator
battery and starter.  All are good.  When I drive and
come to a stop light the interior lights and
headlights dim but when I speed back up all lights
are bright again.  Any ideas where to start?

1 Answer

69,295

Some "flairing" of the lights in relationship to engine speed is normal on a non-computer controlled vehicle. If it's excessive there's a problem. Such as a bad alternator drive belt or serpentine belt tensioner, if equipped. HTH. -Jim

Your Answer

Add photo

Related Questions

  • Alternator trouble 1 answer

    I have a 85 gmc and I've tested the alternator battery and starter. All are good. When I drive and come to a stop light the interior lights and headlights dim but when I speed back up all lights ...

    1985 GMC C/K 10

    -

    Maintenance & Repair

  • 85 GMC C1500 Overheating 1 answer

    My sons GMC overheated last night and blew a hole in the radiator. We replaced the radiator, but it is still overheating. Not sure if this is related to the thermostat or the water pump. Is there a...

    1985 GMC C/K 10

    -

    Maintenance & Repair

  • Brake lights and turn signals don't work on my 85 gmc 6 answers

    I have an issue with my brake and turn signals the front left works but the front right and rear don't, as for the brakes no power going to brake switch. I changed switch and flasher.checked unde...

    1985 GMC C/K 10

    -

    Maintenance & Repair

  • 1971 gmc pickup reverse wont engage 1 answer

    yesterday i reverse worked great but to day it acts like its in neutral

    1973 GMC C/K 10

    -

    Maintenance & Repair

  • Cam selection 1 answer

    I have a small block Chevy 350 with headers, edelbrock performer intake, Holley 650, msd street fighter distributed, and I need to replace lifters so I was going to buy cam and lifter kit what is a...

    1974 GMC C/K 10

    -

    Maintenance & Repair

C/K 10

Looking for a Used C/K 10 in your area?

CarGurus has thousands of nationwide listings and the tools to find you a great deal.

Postal Code:

Shortcuts

Search GMC C/K 10 Questions

GMC C/K 10 Experts

#1 tennisshoes
tennisshoes
Reputation 30
#2 gearheadnard321
gearheadnard321
Reputation 20
#3 AskTrannyMan
AskTrannyMan
Reputation 10
View All

Related Models For Sale

Used Ford F-150
429 Great Deals out of 9,065 listings starting at $922
Used Chevrolet Blazer
16 listings starting at $1,750
Used Chevrolet S-10
12 listings starting at $3,800
Used Pontiac Firebird
24 listings starting at $8,995

Content submitted by Users is not endorsed by CarGurus, does not express the opinions of CarGurus, and should not be considered reviewed, screened, or approved by CarGurus. Please refer to CarGurus Terms of Use.