• Welcome Visitor! Please take a few seconds and Register for our forum. Even if you don't want to post, you can still 'Like' and react to posts.

1991 ranger temp gauge not working


91supercab

New Member
Joined
Apr 8, 2011
Messages
33
Reaction score
0
Points
0
Vehicle Year
1991
Make / Model
Ford
Transmission
Automatic
First off its a 91 ranger with a 3.0 v6. I just changed the thermostat and flushed the radiator because i was have low heat problems and the temp gauge never leaves Cold. Now the truck has better heat but the gauge still doesn't move. I haven't noticed it moving at all over the last couple weeks. It used to move a little but it never would get up to where i thought should be normal. I pulled the plug and ran a jumper wire and still nothing. Weird thing is ...it actually causes the check engine light to come on when i jump it. I was going to just take the easy route out and install and aftermarket temp gauge and call it done..but now i'm worried about having the check engine light if i unplug it. Did the light come on just because i jumped it?? I should have checked it with it just unplugged with no jumper but i didn't.

I also checked it with a test light and it barely lit up...by barely i mean with no lights on in the dark ...i could barely see it. That leads me to believe the wiring or the gauge is faulty. I really would rather just install an aftermarket gauge and call it done. If anyone knows if i can unplug that temp sensor and just install an aftermarket one let me know. This is just my daily beater and not really looking to tear the dash apart to make it look factory.
 


martin

New Member
Joined
Aug 6, 2007
Messages
3,218
Reaction score
26
Points
0
Age
77
Location
St Bruno, Quebec
Vehicle Year
1984
1991
Make / Model
ford
Transmission
Manual
There are two temp sensors, one for the gauge (one wire) and one for the computer (two wires). A bad connection at the sensor is a common problem.
 

91supercab

New Member
Joined
Apr 8, 2011
Messages
33
Reaction score
0
Points
0
Vehicle Year
1991
Make / Model
Ford
Transmission
Automatic
Ok well i must have just found the 2 wire one then. It was right next to the thermostat and inlet neck. Just to the right (if your looking straight at it. Where is the gauge sensor at then?
 

RonD

Official TRS AI
TRS Technical Advisor
Joined
Jun 2, 2012
Messages
25,363
Reaction score
8,369
Points
113
Location
canada
Vehicle Year
1994
Make / Model
Ford
Transmission
Manual
The 2 wire sensor is for the computer, it's often called the ECT sensor(engine coolant temp), it's connector faces up towards the hood.
Since its part of the computer system the CEL came on when you shorted it.
This sensor is used as the "choke" on EFI systems, cold temp causes a run rich setting, then leans out mixture as sensor warms up.
Reduced mileage could mean this sensor is failing.

Just below the T-stat housing and facing forward toward the rad is the 1 wire "water temp indicator" sensor, for the gauge.
It should be next to the screw in elbow fitting for the heater hose, if memory serves.


This is for pretty much any 1 wire temp gauge:
To test the temp gauge, turn on key, unplug the 1 wire on this sensor, jump that wire to any ground, gauge should go to full hot.
If it does then wire and gauge are good, replace sensor.
If it doesn't then either wire or gauge is bad, sensor might be ok.


These are resistance sensors, as temp rises resistance is less so gauge goes up, grounding the wire is 0 resistance which maxes out the gauge, no it won't hurt it.
Because of the way these sensors, and other 1 wire sensors work, don't use tefon tape to seal them, you can put sealant on the upper threads but leave the lower threads bare for a good ground.
 
Last edited:

Sponsored Ad


Sponsored Ad

Staff online

Today's birthdays

Member & Vendor Upgrades

For a small yearly donation, you can support this forum and receive a 'Supporting Member' banner, or become a 'Supporting Vendor' and promote your products here. Click the banner to find out how.

Truck of The Month


Shran
April Truck of The Month

Recently Featured

Want to see your truck here? Share your photos and details in the forum.

Follow TRS On Instagram

TRS Events

25th Anniversary Sponsors

Check Out The TRS Store


Sponsored Ad


Sponsored Ad

Sponsored Ad


Amazon Deals

Top