I have an 89 TBI RS. My oil pressure guage does not work. Which sender or sensor controls the guage? There is one just above the oil filter and another just above the starter. Which one does what?

 

In your car, it should be next to the dist. Itll be a metallic canister screwed into a fitting on the china wall.

 

I will have to go look for that. however, what is that sender with 3 wires just above the oil filter. Somone told me it was a sender/sensor combo.

 

Sounds like it could be the combination sendor/switch. In the later years gm phased out the sendor for the oil pressure and combined them into one part.

 

The one you have with 3 wires right above the oil filter is your oil pressure sending unit. Older models used a different method as dimented24x7 described. The one you are referring to right above the starter is your fan temp switch. It turns on your fan when the coolant reaches a certain temperature.

 

My guage just started reading wacky the other day. I guess I'm gonna have to get this freakin thing fixed too.

 

I believe the sending unit above the oil filter is for the oil pressure guage and also a fuel pump cut off switch. If your oil pressure guage is going whacky it's probably the sending unit. I've had to replace two.

Steve