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View Full Version : Colant temp? on 94 Jimmy 4.3L

Snoworks
11-28-2003, 10:45 AM
I have a 94 GMC Jimmy 4.3L, this is the problem: If I start the engine when it is cold, the digital dash shows the water temp as overheating. Would this be a colant temp sensor issue?

Chuck B.
wyldman
11-28-2003, 11:03 AM
Try disconnecting the temperature sender,and see if it stops.If it does,it is most likely a bad sending unit.

If not,check for a grounded sending unit wire.If that looks OK,it may be the dash unit that has gone bad.
Snoworks
11-28-2003, 06:24 PM
Ok - help me out again. There are two colant temp sensors on this truck, yes. Where are they located.

Chuck B.
wyldman
11-28-2003, 07:44 PM
The sensor for the dash gauge should be in the left side (drivers side) cylinder head,between the first two cylinders.
Snoworks
11-28-2003, 07:51 PM
Chris - when you say sending unit, you are refering to the sensor, correct?

Chuck B.
wyldman
11-28-2003, 07:57 PM
Sending unit,or sensor,they are basically the same thing,just different terminology.

When you get a new one,make sure it's for the temperature gauge and not the CTS,or Coolant temperature sensor for the computer.
Snoworks
11-28-2003, 08:02 PM
I will check the temperature sensor like you suggested. If it is bad I will replace the CTS and this sensor. If it is good, I will change the CTS only.

Thanks for your help.

Chuck B.
wyldman
11-28-2003, 08:58 PM
Do you know if the CTS is bad ? A good scanner would tell you quite easily.I wouldn't just replace it unless you've verified it's operating out of spec.
Snoworks
11-28-2003, 09:45 PM
Where can I get an adapter to fit my 94 Jimmy. I have a Snap-on Micro-scan, but it only fits newer cars!

The Snap-on guy will take a long time to get a hold of.

Chuck B.
Snoworks
11-29-2003, 01:00 PM
Chris - I unplugged the sensor between #4 & #6 cyl. and it still did the same thing. Only difference is that the check engine light came on the second I unplugged the sensor.

Chuck B.
wyldman
11-29-2003, 01:46 PM
Maybe it is backwards on your truck,and you unplugged the CTS.I'm at home,so I can pull up any info here,but as soon as i get back in the shop,i'll let you know.
Snoworks
11-29-2003, 02:23 PM
I unplugged the sensor that is between the #1 and #3 cyl. When i started the car no reading is shown on the dash. So this must be the temp sensor.

Does the temp sensor have any input to the computer of the car, or is it strictly for temp readout?

Chuck B.
wyldman
11-29-2003, 02:49 PM
Yes,that would be the temp sender for the dash gauge.It is not related to the computer at all,that's what the CTS is for.
Snoworks
11-29-2003, 03:50 PM
So temp sensor is bad, which means a trip to the dealer!

Chuck B.
Snoworks
12-01-2003, 08:33 PM
Chris, thanks for the help. The new temp sensor did the trick.

Chuck B.
wyldman
12-02-2003, 05:02 AM
Great,you fixed it!