1995 Camry temp gauge issue

[brian79z]

Temp gauge starts out beyond HOT as soon as the key is turned on, and stays there regardless of the drive. car will drive for hours without any issue with overheating.

Temp sender with the greenish-gray connector has been replaced (the only one available at the auto store).. but there looks like 2 other temp sensors/senders on the thermostat housing.

Problem still exists. Disconnecting the new sender will result in a check engine light. Reconnecting removes the check engine light. This should verify that the wire is not broken anywhere, or else I would get a check engine light.

Should I have replaced one of the other sender/sensors? What sender/sensor is for what?

[Stillrunning]

If this is a 4 cyl'd then the center unit is the gauge sender. It has a single Yellow/Green wire going to it. The temp gauge test is to ground the sender wire and the gauge will go to max hot, which means the gauge is good. If you replaced the correct unit then it sounds like the wire is grounded somewhere.

[hill8570]

OK, assuming we're talking about the 4-banger, StillRunning pretty much hit it. Standing at the radiator and looking toward the firewall, you've got three items in a row near where the upper radiator hose goes into the engine.

The one on the right (usually blue) with two vacuum hoses going into it is the purge valve for the charcoal canister.

The middle one (usually grey with a single wire) is the sender for the temp gauge. This is the one you need to test and / or replace.

The far left one (usually green with two wires) is the coolant sensor that the ECU uses for calculating fuel mix, etc. Sounds like that's the one that you replaced.

[brian79z]

Yeah.. without going out & looking under the hood... I think it was the one all the way to the left. It was the only one sold at the parts place. I'll verify tomorrow.. and maybe search harder for the correct one.

Now if I could only fix both of the left power windows. I can hear a faint whine noise when I hit the switch, but no movement. Thinking the motor and/or reg is tied up.

[hill8570]

Originally Posted by brian79z

Yeah.. without going out & looking under the hood... I think it was the one all the way to the left. It was the only one sold at the parts place. I'll verify tomorrow.. and maybe search harder for the correct one.

If you have a u-pull-it junkyard nearby, you might want to try that route. That sensor is pretty reliable.

I'd first check the operation of the gauge itself. Just pull the connector off of that middle sensor, and start the car. If the gauge doesn't go to full cold, then you've got a problem in the gauge or the wiring to it, so no point wasting your timing trying to replace the sensor.

Originally Posted by brian79z

Now if I could only fix both of the left power windows. I can hear a faint whine noise when I hit the switch, but no movement. Thinking the motor and/or reg is tied up.

Regulator tends to be a bit iffy on those guys. I've never had to replace one, but search the forum here -- I know I've seen discussions from other folks who have had to do it.

[dmkinsey]

Sounds like this is the same condition I have with my '93 I4. The temp gauge started being erratic and after a couple days of that it just stays around 25%. It always used to stay at 48%.
I replaced the thermostat with a genuine Toyota part. No joy. Then replaced the ECT sensor. Had to go to Autozone for the ECT, it's Sunday. No joy again.
So I disconnected the wire from the gauge sending unit, the needle stays on the peg,full cold indicated.
I don't see any info about the gauge sender in the Haynes manual. should I just put black tape over my gauge and be happy?

[93celicaconv]

Originally Posted by dmkinsey

Sounds like this is the same condition I have with my '93 I4. The temp gauge started being erratic and after a couple days of that it just stays around 25%. It always used to stay at 48%.
I replaced the thermostat with a genuine Toyota part. No joy. Then replaced the ECT sensor. Had to go to Autozone for the ECT, it's Sunday. No joy again.
So I disconnected the wire from the gauge sending unit, the needle stays on the peg,full cold indicated.
I don't see any info about the gauge sender in the Haynes manual. should I just put black tape over my gauge and be happy?

When you removed the wire from the coolant temperature sender and saw that the gauge went to full cold, the gauge operated at it should (infinite resistance is read as extremely cold, -40 deg F).

What I would test next is taking your disconnected wire, and ground it to something on the engine, then see what your temperature gauge is reading. If it is pegged HOT, then I think your gauge (and wiring from the sender to the gauge) is working just fine.