87 LG4 (Auto)- On the Drivers side of the firewall between the fender and power brake unit is a bracket holding 4 different relays.

Closest to the fender is the 'VAC' (I think), having 3 wires and a vacumm post.

Closest to the P/B is the 'ESC' (I think) having 5 wires and a rubber seal.

Hanging just in front of the 'ESC' is a 5 pin
relay. What is the proper name for that and what does it control?

Nearly identical to that one is a 4 wire relay that hangs between the 'ESC' and the 'VAC'. What is the proper name for that and what does it control?

I'm just trying to get a better understanding
of the wiring system and what relates to a non-cc Engine/Ignition and which systems are just taking up space.

Thanks for your help and time.

 

You are correct about the ESC and the "vac" sensor. that is about what they are.

As for the relays, the one with the fat ORN and TAN wires is for the fuel pump. Before you even ask, YES YOU DO HAVE AN ELECTRIC PUMP IN THE TANK. The other is for the cooling fan.

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'97 Bonneville SSE

 

Thanks GM. How did you know that was one of my nagging curiosities?