What is this relay for?

[Bagged Dually]

While working on my truck this evening and removing some old wiring I noticed a wire had been cut by a previous owner. The wire is coming out of a relay mounted on the inside of my drivers side fender a few inches from the firewall. The relay itself is more of a rectangle shape and is definitively a factory GM installed part. The wire that has been cut is a heavier gauge solid red wire.
Does anyone have any idea what this relay is for or where the other end of the wire might be found.
The truck has a stock TBI 454 in it so I'm guessing it might be the fuel injection or an accessory of some kind. Just a hunch though.

 

[davbell22602]

voltage regulator? brain box?

 

[RetroC10Sport]

We would benefit from a pic.

 

[Bagged Dually]

I'll see if I can get a pic up in the next few minutes.

 

[bucket]

voltage regulator? brain box?

Yep, that must be it

 

[crazy4offroad]

voltage regulator, brain box.

Voltage regulators are built into GM alternators Dave. And I dont think he appreciates you calling him "brain box" lol

 

[bucket]

And I dont think he appreciates you calling him "brain box" lol

 

[Bagged Dually]

thats the relay on the fender right behind the hood hinge....Hopefully the pic uploaded this time...

 

[crazy4offroad]

Looks aftermarket to me, does it have driving lights or an electric fan?

 

[Bagged Dually]

It's got a single electric fan for the factory AC I had assumed. It has the factory manual fan and the electric is mounted on the front side of the radiator. Did these trucks ever have an electric fan with AC. What made me think it was factory is that it's wired in with all the factory wiring loom.

 

[Joeairforce]

Nope not factory.... Sounds like it's for the aftermarket fan a P/O installed.... It's easy enough to route stuff into the factory loom if the time is taken to do so...

 

[RetroC10Sport]

Yes, they did have an auxiliary fan mounted in front of the radiator. I've seen the relay there before and that's likely what it is for.

 

[crazy4offroad]

I downloaded the pic and zoomed it in, I see the factory looking connector on the bottom but with all those wires running everywhere I assumed it was for something like lights. I would start the truck and unplug the relay while it's running and see if it dies, I'm thinking it may be a fuel pump relay if it's TBI. If the truck has the a/c radiator I would say that's what the fan is for but if it just has a regular radiator then I would say it was added on, and the wires probably go to a temperature switch to make it come on, and the relay might supply the higher amp power for the fan.

 

[Joeairforce]

Yes, they did have an auxiliary fan mounted in front of the radiator. I've seen the relay there before and that's likely what it is for.

Well that's news to me... Never seen that before...

 

[RetroC10Sport]

I'm surprised your Sub doesn't have one.