1986 truck intermitent warning lights

[snaggletto]

Hello, my A/T temp, charge, and brake warning lights have been blinking on/off randomly, but always all 3 of them at a time. Even sometimes right after a cold startup, so I know the at temp light is bogus. Some kind of short or something. Any ideas on where to start looking. The truck seems to drive fine whether the lights are on or off. Thanks for any tips.

 

[jynx]

Alternator would be my guess. Have it check if you can then go from there. Could be bad connection in charging system or something else, but I am guessing it is in the charging system.

 

[snaggletto]

I could stand to get the alternator load tested. Thanks for the tip.

 

[PGH854runner]

had this exact thing happen to me last summer on a road trip from Pittsburgh,PA to Hatteras,NC......all three lights came on scared the shiite out of me......had the alt tested at Napa in Buxton,NC and it was good.......finished the trip with no troubles(minus a blown out header-cat gasket....but i dont consider that related) and the light eventually went out

 

[Doable]

Check see if you have brake lights or if the brake light fuse is blown.Weird I know. My brothers LandCruiser was acting the same way and the only thing we found was a blown brake light fuse.

 

[snaggletto]

Update. I noticed my idle speed changes as well as my blower motor speed as the lights flicker on and off. I checked voltage at my battery with the engine running and I got 18v. Definitely a regulator problem.

It appears that the regulator was separate from the alternator for some years, but I believe that the regulator is on the back of my alternator. I'm thinking I might be ahead if I just replace the whole alt/ regulator assembly...