flatbush862

I have a 1990 a4. The coolant temperature gauge on the dash stopped working. it is flat 0. The other gauges all work fine

I changed the coolant temperature sensor on the intake manifold and it still does not work.

Looking at the Haynes Manual 1 line diagram, it looks like there is something called an

"Engine Metal Temperature Switch" feeding the gauge.

Could this be the problem?? Where physically is this in/on the car??


I have a PCM for less chip in the car.

Help with this one appreciated.

Flatbush 862

AGENT 86

On my 86, the gauge info comes from sender in passenger head. It sounds like you replaced the one the ECM uses.

flatbush862

Yes thanks Agent 86-

After researching a little bit I found the correct part and location. The auto parts stores often confuse the temperature coolant "sensor" with the coolant "sending unit" the sending unit is as you said on the passenger side head near the #6 cylinder plug. The sending unit has a blade connection where as the "sensor" is a socket connection at the front of the intake manifold under the Throttle body.

Flatbush 862

macatxfl

Hi there is a sensor on the passangers side of the car close to the back of the motor right next to the back spark plug ,,,That sersor controls the temp gauge the one on the mainifold is just a temp switch check that back senson there is 1 single wire that mounts to it some times that wire gets melted or just gets loose and falls off the ground prong and when the wire falls off the gauge will NO longer WORK as this happens to my 1990 c4 with the L98 motor in it when that wire falls off too it stops sending the temp of the motor to the ECM and turns the gauge off and some times sends a check gauge signal to the info centor on the dash Hope i helped some

TomP.

I just bought a 1990 Corvette and the Temp. gauge was not working all so . I all so looked at the sender at the front of the engine as that is were Chevy used to put the Temp sender . I would have never looked by the right rear spark plug . Sure enough there it was with the wire disconnected . I reconnected it and now the gauge work's fine . Thanks for the help .

F0RMULA

Similar thing is happening with my 92 LT1.

The gauge just randomly stopped working, BUT the digital coolant temp. readout still works.

Could it still be that part on the passenger firewall?

rodj

Gauge sending unit is located in head as noted above

Because it uses a different sensor

rodj

For anyone who has found this by searching; info is wrong
The " just a temp switch" is the coolant temp sensor (CTS ) located in the intake at front that sends engine temp to ECM and is a major item in engine control
Sending unit in head only runs the temp gauge

TomP.

The temperature sending unit in the right head is needed for the analog temperature gauge located in the dash to work . If it worked once and a while the wire connector was loose and now is disconnected . The sender is located next to a spark plug so when changing plugs it gets knocked off .

F0RMULA

Thanks for the help!

When you say 'RIGHT Head' are you talking passenger side or driver side? And I'd imagine its more towards the firewall?

thanks again

TomP.

The passenger side just in front of the spark plug closes the fire wall is where You will find the Temp. sender . The wire is green and it is a single connector . Have Fun !!!

engle1147

sender for the cluster circled in green.

F0RMULA

exactly what i needed to know/see


thanks

gypsydiego

I found the sensor, where am i suppose to connect it to?

Tony Velasquez

It goes up an down but mainly stays on 299 .... So i put an after market gauge an my temp stays at 190...but im trying to keep it original

Cliff Harris

It connects to a green wire with a blade style connector:

WVZR-1

Cliff - Post #14 is 30 months old and #15 is a very vague inquiry mentioning NOTHING about the car!

POSTER "Tony Velasquez" - What year is your car? It would likely be suggested by some that you post a NEW thread but since you're here mention more information about your car. Year, engine, transmission etc.

You mentioned "stock" - shouldn't be an issue!

Tony Velasquez

Well its a 87 vette with the 5.7 tuned port engine. My temp gauge is going crazy , but whats so funny is i dont even have it conected i dis conected the one in front an the one on the side because i figured that since i disconnected the temp sending unit an that done nothing it still kept marking it goes from 250 to 299 but mainly stays on 299 can their be another one located some where else

bob arrowsmith

make sure the wire is not corroded or brocken some where down below the manifold , if it is and it touching metal it will cause your gauge to bounce around , this would be the sensor switch as said on previous post on passenger side, if it is disconnected the analog switch will not read any tempeture, i have an lt1 and there are two temp switchs the one in front is for the digital read out on the dash. if you disconnected that one please reconnect it , your car will run terrible. the ecm uses this for proper tunning , idol, and cooling fan control.