I have searched this forum and google for information regarding why coolant temperature sensor gauge on my 94 Cherokee 4.0L is at zero. When I turn the ignition the meter pegs hard right and then settles back to zero.

The gauge has been this way since I bought the car a few months ago (150K miles), apparently it was not needed to pass smog in CA, but common sense tells me I should fix the damn thing. Just the other day I recently changed out the radiator and when I did that I changed out the Coolant Temp Sensor, which I thought would aid in solving it, but that did nothing.

Is there something I'm missing?
Do I need to replace my T-Stat Thermostat as well?

I've found a few threads on this forum that discussed similar issues, but no resolve was discussed. One thread mentioned that it might be a cracked gauge. I will tear apart my dash in the next day or so to see if it is damaged or not.

Any ideas, links or pointers would be appreciated.

 

Do not fool with tearing apart your dash. I had a similar problem but my temp gauge was operating, it was just reading wrong. I tried to replace my coolant temp sensor and nothing helped. I purchased a small Sunpro Temp. Gauge from my local AutoZone/ Advanced Auto. The gauge was mechanical in nature so I had a garage install a metal "T" into the T-stat housing where the coolant temp. sending unit is. So one side of the "T" was screwed into my T-stat housing, one side had the new gauge sensor screwed in and the other end had the Coolant Temp. Sending Unit on it. Worked like a charm!!! The only down side was the stock gauge read a very wrong temp but the new Sunpro gauge was right on!! Let me know if you need any other details. Good Luck!!

 

LCFR may be right but it is worth a shot to pull your guage cluster and clean the contacts. I think you have a 50/50 shot at that being the culprit.

 

There are TWO sensors that deal with engine temperature

1. Coolant Temp. SENSOR
2. Coolant Temp. SENDING UNIT.

1. SENSOR: Sends temp info to computer to allow it to adjust fuel enrichment. This is located in the thermostat housing and has TWO wires in a water-tight connector.

2. SENDING UNIT: Sends temp info to the GAUGE. Located on the left rear corner of the head. (driver's side rear) Right next to a valve cover bolt and just forward of the engine ground (rear head bolt) This SENDING UNIT has ONE wire that is pressure fitted onto a single round fluted prong.


IF SENSOR is defective, most times you will get a CEL (Check Engine Light) with a stored code of CODE 14 or CODE 15.

IF SENDING UNIT is defective, you will get a false reading/non-functioning gauge.

Best shot I could get of a TEMP SENDING UNIT. This IS from a 94 model:

 

Good catch Howler I forgot it was an OBD Jeep. I was thinking Renix.

 

Dumb Question....

The sending unit only has one wire?

Looking down into the plug of the part I bought I only see one terminal. Is this correct?

 

2. SENDING UNIT: Sends temp info to the GAUGE. Located on the left rear corner of the head. (driver's side rear) Right next to a valve cover bolt and just forward of the engine ground (rear head bolt) This SENDING UNIT has ONE wire that is pressure fitted onto a single round fluted prong.


So you are correct

 

Hi

sorry to hijack thread, i am after a sending unit, my local dealer is a bit clueless as there are 2 he says andhe is giving me 3 prices, £117 , £40 and finally £22 for a sender. code number for jeep he says is 56027012 can anyone tell me a correct price and code number for these. Thanks

i am in the uk by the way

 

anyone???

 

Howler, I want to thank you so much for pointing out 2
temp senders on the 95 grand cherokee. The factory
manual was inacurate and misleading. I was spinning till
I read your post, saved me alot of time.

 

'84-'96 Coolant temperature sending unit
Mopar: 56027012
Niehoff: TS82771/AL6206

This is the sensor located at the rear of the engine near the valve cover as described. It sells for 10 dollars

 

I also recently purchased a Temperature Sender unit which is located in the front of the engine at the thermostat. It regulates engine operation based on temperature sending data to the computer.
1994 Jeep Grand Cherokee Laredo
OEM part number 9364 Cool Temp Sen. (written on the box)
It too sells for 10 dollars.

 

Make sure the groung strap from the motor to thr firewall is not broke and has good contact. Had the same prob with my daughters 87 and the strap was broke replaced it and it works like a champ.

 

I had the same issue on my 94 xj. I did some testing and it turned out to be the map sensor

 

Thanks for the info on the rear sending unit as opposed to the sensor. Huge time savor. There is a single purple wire in a plasting housing that looks like it might have gone through the firewall, into the cab and connected to somewhere under the dash. Could someone tell me the endpoint of this purple wire? Did it go to the back of the gauge or did it connect somewhere else? Previous owner hacked the crap out of this poor 94 XJ.

Thanks