well guys... basically... my heater grid, ac/heat fan, low fuel light... don't work... oh and its not charging(new alt).... I'm thinking its maybe the ''brain box''... on firewall next to where the steering shaft comes out??? I'm not saying all these are related but I'm kinda at a loss... i've checked all the fusible links i can find... any help is appreciated.

 

What year is this truck?

 

1990... .sorry.. and i don't wanna do the external regulator deal just yet... i would like to try and fix it... i haven't even bought a new factory regulator yet... i am just trying to get ideas..

 

Unless I'm mistaken, you have no choice as your regulator is already external. Pretty-much located in the center of your firewall, just above the engine. ?

 

i was under the impression it was built into the brain box or whatever u call it.. even still that doesn't explain the other stuff that all quit at the some time does it??

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does anyone have any ideas???

 

I know in the later 12 valves all that stuff is controlled by the PCM, not sure about the first gens though. Might not hurt to check all your grounds.

 

- The 1991.5 and earlier trucks have the voltage regulator mounted on the firewall. It is a separate device from the PCM.

- The 1991.5 and later trucks have the voltage regulator integrated with the PCM.

 

u are correct!!! still didn't solve my problem... my new regulator went bad in about a month..

 

My intercooled '91.5 has the voltage regulator on the firewall....

 

Could be your ignition switch. Mine did funny things like that before I replaced it.