I have a lower mileage near perfect 1988 IROC with the 5.0 TPI 5-speed manual. The temperature and oil pressure gauges do not work. I’d like to get them working again. Other than the sensors or sending units, what should I be looking for?

 

I can't offer any first hand experience, but I can take a stab at it.

Do the gauges read anything at all, or are they just dead? If they peg out when on, I may look into replacement gauges. A whole cluster may be upwards of $150 or $200, but individual gauges will go for a bit less. If the gauges are just dead, I may use a multimeter can check for voltage. I probably pull the gauge first, and check the sockets where it plugs in. If no voltage, check the sender at the engine. Electronic issues are a pain, but bad gauges and bad senders are definitely a thing. I'd definitely start there.

 

Thank you for the reply. Sounds like a reasonable plan. I’ll move forward

 

Have you look at the wiring at all?

 

A quick check for the coolant gauge is to unplug the green connector in between plug wires one and two and check the coolant gauge the gauge reads full cold then next ground that connector to the block in the gauge should read full hot.

This will rule out the gauge. The same rule can be applied to the oil gauge as well.

for the oil pressure sender you're looking for a tan wire leading to a dome shape device behind your plenum on the back of the block attached to a pipe fitting. It should have one wire connector on it. that dome shaped device is your oil pressure sending unit for the gauge.

Using the same procedure above the results should be the opposite for the oil pressure gauge.

See the attached picture out of my 87 electrical manual. The procedure should be similar if not the same for the 88. Also attached to the picture of a oil pressure sending unit for reference. If you determine that yours is bad make sure you get one for the range of your gauge. there are two for a car one for a 60 PSI and one for an 80 psi gauge. The one for my car for example was 60 PSI.

 

Great Post !