Temp and oil gauge not working?

[Rockstar]

I noticed on my gauges that the two most important gauges arent working, the temp and oil presure gauge. The RPM, volt and fuel work but not those two. How can i test them to see if its just a wiring issue or if something isnt hooked up? Discount autoparts has autometer gauges on sale for 9.95 in black and white face but i dont want to have to run the hoses and wiring if i dont have to. Plus im not sure where to tap into for getting the accurate reading. So ill start with suggestions on testing what i have then ill go with plan B. Thanks

 

[megaladon6]

what kind of car?
is it a true temp gauge or just the stupid overheat light?
find the gauges and groung the connectors one ata time. see if the gauges move.

 

[srercrcr]

Sounds like gauges...gauges are gauges, lights are lights.

 

[megaladon6]

you never know. i double check everything.

 

[Rockstar]

They are gauges. Its an 88 Monte. I just walked out there to look at it and the temp is sitting where it would sit if the car was not running and the temp its pegged past 60. How do i ground it to see if they move? Also my Tach seems to be off when reving the engine its shows im redlining but im barely give it gas how can i adjust that also? Thanks

 

[megaladon6]

to ground them just disconnect the wire and hold it on a piece of bare metal in the engine compartment. temp should go to full. it sounds like the oil press is shorted to gnd already.
the tach may be related, but it sounds like a bad tach filter. mine does the same thing.

 

[Derision]

I'd pull the dash off and check the connections behind the gauges. A similar thing happened to me; my gas gauge stopped working, and the needle was pinned all the way past F. Also, the "TEMP" idiot light stopped working. The symptoms indicate a bad ground, but the ground for the gas gauge was perfect. Turns out it was that awful circuit celophane thing on the back of the gauge cluster that was bad.

So I'd check that. And I just discovered, care of this board, that you can fix bad wires back there with rear window defogger repair stuff.

 

[ryanelco]

try to see if the senders have corrosion or if they are even connected. The temp sender is located in one of two places, one is in the driver side cylinder head, it looks like a spark plug at first glance, but should have a thin wire connected to it, if not your gauge is not connected, or the contact may be corroded check and see that everything is clean. or the wire may have melted insulation and may be grounded out. the oil press. is either directly behind the distributor or near the oil filter, do the same for that one. if this does not work buy new sendors. as far as the tach, chances are the filter is bad. it is a small cylinder located on the firewall with wires going in each side, if you really need your tach to work, you can clip the one side and put a female connector on it and hook it up to the tach terminal on your distributor. hope this helps, good luck.

 

[Rockstar]

Thanks for the help ill have to check it later when im out of work. The temp sensor wouldnt be on the top of the thermostat housing would it?

 

[85 Cutlass Brougham]

No, that's the coolant temp sensor. It can be next to the thermostat housing screwed directly into the manifold though, and will have I believe a dark green wire running to it.

To me, it sounds like a bad connection at the back of the cluster. It gets contact when the cluster is screwed to the dash, and does not have an actual positive connection with a connector that snaps in place. I cleaned my dash-side contacts with a scotchbrite pad and bent the brass contacts out a little to give better contact. You could probably use a pencil eraser to clean the cluster-side contacts. I would also inspect the printed circuit on the back of the cluster as they sometimes do go bad and come apart.