My temp guage went out this afternoon. It was working this AM, was working at kunch, and was working until I stopped on the way home to get a cuppa coffee.
Nothing. Dropped right down to the pin. I don't like driving without a temp gauge, esp in a car noted for eating headgaskets.
Any idea what to look for? Can I apply a voltage somewhere to the instrument cluster to get a reading?
Can I check a plug going to the inst. cluster to look for a voltage?
How can I check the sending unit?
Any ideas
Got a Haynes for it? Try changing the engine coolant temperature (ECT) sensor?
If it's shot, your voltage will probably read 0.0 V ;)
Unfortunately, I have Haynes for the other three Toyotas I have...
You'll need a wiring diagram to know which instrument cluster pin to energize.
Again, you'll need a wiring diagram to know which pin to check.
First, see if the wires to the sending unit (I think it is on or near the thermostat housing) is connected and the connector didn't corrode off. If it is a 2-wire unit, then you should have 12 volts going in and varying voltage coming out, depending on coolant temp. If you have 0 out, then the sender is bad. You may be able to confirm by cannibalizing a sender from one of your other Toyotas.
Note the color and tracer for the wire for the variable side of the sender. It is probably the same color going into the instrument cluster. If you are getting voltage out of the sender, you can check for the same voltage at the cluster. If the voltage is not the same, then you may have a cut in the wire or a loose connection between the sender and the cluster. If this is the case, finding the fault in the wire or connection is going to be a big job. Just run another wire from the sender to the cluster and use a Scotch lock at each end if you don't feel like soldering.
Check where the harness plugs into the sender first and carefully bend the tab in the female side of the connector carefully if it is loose.
I don't know why sometimes I lose my 'confidence'. Perhaps sometimes I just need a gantle 'nudge'.
I was doing the usual 'maintenence' on a car this old this AM, check the oil and other fluid levels and just give it a general once-over under the hood, and I looked at the thermostat housing. Then I saw the connection, about 1/3 to 1/2 off the lug, and the lug kind of a sickly green color. I pulled the connector off, pushed it on all the way, pulled it off and fully reconnected it again.
No problemo! Thanks for the 'nudge'!
You may want to wipe the green slime off the tab and apply some fresh dielectric grease.
Happy motoring!
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