I know one is the ac clutch relay. One is the ac blower motor power. One is the starter relay.
Probably the ac compressor clutch relay, the starter relay and the HVAC blower motor high speed relay.
It is mounted under the drivers side of the truck in the frame rail.
Under your hood. To the right of your brake master cylinder. Two relays are located there.
That would be the drivers side frame rail under the truck.
get under the truck disconnect hoses unmounted old fuel pump...mount new pump reconnect hoses.
You can use drive on ramps or a floor jack under the cross-member and support it with jack stands under the frame.
There are some relays under the hood on the firewall and some more relays in the back of the glove compartment, it all depends on which relay you are looking for.
under the steering colume
under hood on drivers side in fuse box!!
In a 1991 Chevrolet C2500 pickup truck, the computer is typically located under the dashboard on the passenger side. You may need to remove some panels or components to access it. It is a rectangular metal box with various electrical connectors plugged into it.
under the truck.
the car has several relays in the fuse box under the hood
under neath the truck