No heat/ temp. Gauge not working

Tiny
HRBANDMAN
  • MEMBER
  • 1998 FORD RANGER
  • 4 CYL
  • 2WD
  • MANUAL
  • 134,000 MILES
I just replaced the thermostat in this vehicle and still the heater won't work and the temperature gauge won't budge. What else can it be?
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Wednesday, April 7th, 2010 AT 6:32 PM

20 Replies

Tiny
RASMATAZ
  • MECHANIC
  • 75,992 POSTS
Check the heater core if its clogged and also the heater control valve functions
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Wednesday, April 7th, 2010 AT 6:47 PM
Tiny
MIKEHAYCOCK
  • MEMBER
  • 2 POSTS
  • 1997 FORD RANGER
  • 180,000 MILES
The temp guage on dash does not work, is this from the ect or iat. Where is the ect?Would this cause pinging going up hill, I use premium gas w octane booster pinging wont go away
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Thursday, April 4th, 2019 AT 1:36 PM (Merged)
Tiny
HMAC300
  • MECHANIC
  • 48,606 POSTS
No the pinging isn'tfrom using premium gas or booster, it can be from to much carbon on piston raising the compression to a bad ect to a lot of things. Attached you'll find apic of ectlocationfor a 2.3L as you didnt' give engine size. The gauge could be bad though you have two ect's one for the gauge and one fo the pcm. On the ect gauge one groudn the woire and see if gauage goes up if it does then teh sender is bad if not it'sthe gague maybe
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Thursday, April 4th, 2019 AT 1:36 PM (Merged)
Tiny
MIKEHAYCOCK
  • MEMBER
  • 2 POSTS
Question restated, also, I use the booster to prevent pinging-it is a 2.3-the service engine soon light will not illuminate-ive changed out the bulb -and no input data from the test port-basicly is it ok to let the engine ping up hill 10 miles a day -i travel to mtn. Pass ca 5 days wk
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Thursday, April 4th, 2019 AT 1:36 PM (Merged)
Tiny
HMAC300
  • MECHANIC
  • 48,606 POSTS
Try replacing yoru kock sensor
check your connection at the aldl and fuses underhood maybe the mil light will come on then.
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Thursday, April 4th, 2019 AT 1:36 PM (Merged)
Tiny
BELLEAUT
  • MEMBER
  • 4 POSTS
  • 1989 FORD RANGER
  • 2.9L
  • 6 CYL
  • 2WD
  • MANUAL
  • 60,000 MILES
I have replaced the sending unit because my temp gauge does not work and I am getting code 21 and 42. 21 is missing temp signal. I tested the gauge wire by grounding the wire to make the gauge read hot. New sending unit and old one did not make the needle move at all.

Could it be the sensor?

I am getting mixed messages about where the sending VS the sensor is. I believe the sending unit has one post on top with one wire pressed onto it. (Replaced it with no change on the gauge)

The sensor is bigger and has a gray wire clip on top of it. Looks like two wires running in and out of it. Does this sensor have anything to do with the gauge? Is there a test?
I am at a loss. I have read so many posts on so many different sites that I cannot tell how many sensors I should be looking for. I cannot find anything on the back of the engine.
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Thursday, April 4th, 2019 AT 1:36 PM (Merged)
Tiny
HMAC300
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  • 48,606 POSTS
It's a two wire connector with a gry /yellow wire and blk/white wire the black white goes back to gauge. Code s21 may be a bad ecm or poor connection for code 42 check fuel pressure key on engine off should be 30-45 psi if higher it may be pressure regulator or leaking injectors.
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Thursday, April 4th, 2019 AT 1:36 PM (Merged)
Tiny
BELLEAUT
  • MEMBER
  • 4 POSTS
Thank you for the feed back. When I ground the single pole sensor the gauge goes all the way to Hot. That tells me the single pole sensor goes to the gauge also. Am I wrong on that? I will check the fuel pressure next.
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Thursday, April 4th, 2019 AT 1:36 PM (Merged)
Tiny
BELLEAUT
  • MEMBER
  • 4 POSTS
Fuel pressure test had bad results. The key on engine off produced 0 pressure. I could hear the fuel pump but no pressure.
When I started the engine it rose to 30.
When I turned the engine off it started to drop right away. I then turned the key back on but did not start it. The pressure jumped a little bit but still continued to fall.
How to figure out where the leak is?

The trunk only has 60,000 miles on it and it has sat for a long time. I have put a little less than 200 miles driving it home and trying to tune it up.

When I take the large rubber hose off of the intake manifold there is a strong smell of gas, I do not know if this will tell me that it is the fuel regulator or a leaking fuel injector.

When I replaced the plugs the plugs that came from the same side as the regulator were much darker. The three from the other side looked normal. Lighter burn color. Not black.
Thanks again.
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Thursday, April 4th, 2019 AT 1:36 PM (Merged)
Tiny
HMAC300
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Because the pressure drops right away try the fuel pressure regulator it shold keep pressure for at least 5-10 minutes before dropping. The temp sensor is supposed to be wired like I said the blak/wht wire goes back to gauge. So look for another wire and recheck the part. After looking at sensor I think you have the wrong sensor. I'm sending a pic of correc part, wired connector and location.
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Thursday, April 4th, 2019 AT 1:36 PM (Merged)
Tiny
MICKEYADAMS
  • MEMBER
  • 1 POST
  • 1989 FORD RANGER
Engine Cooling problem
1989 Ford Ranger 4 cyl Two Wheel Drive Manual

Temp guage isn't working, suspect sending unit. Where is it located as I've been told it has two?
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Thursday, April 4th, 2019 AT 1:36 PM (Merged)
Tiny
BLUELIGHTNIN6
  • MECHANIC
  • 16,542 POSTS
Hello and thanks for donating

Your vehicle has a coolant temperature sensor as well as a coolant temperature sending unit. The sending unit is used for the gauge, the sensor used for the cooling fans. The sending unit for the 2.3L is on the left rear of engine, above the oil filter. For the 2.9L it is on the intake manifold, below the throttle body.
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Thursday, April 4th, 2019 AT 1:36 PM (Merged)
Tiny
BELLEAUT
  • MEMBER
  • 4 POSTS
Hmac300
Your information was spot on. The fuel regulator was bad. I replaced it and the truck is running much better now.

I still have the original problem of my temperature gauge not working. The pictures really help. (The best I have seen so far) I did find both, the coolant temperature sending unit and the ECT. I replaced the sending unit with no change on the gauge. I believe I already wrote this in a earlier post so I am sorry for repeating myself. I replaced this one based on a youtube video I saw. The video was based on a truck that was much older than mine. The truck in the video probably did not have an ECT or a computer for that matter. (No fuel injection.)

My confusion is based on the test from the video. I grounded the only wire that connects to the Coolant temperature sending unit, turned the key on and the temperature gauge inside the truck bottomed out on the hot side. In other words it moved. If nothing else is it safe to say that the gauge should work once I find the problem?

After I read your post and looked at the picture I pulled the ECT. I did an OMS test on it and I also check for resistance using hot water. The ECT tested positive. My guess now is a bad wire somewhere. I tried to do a voltage test on the ETC wires. With the key on I did get some voltage off of one wire. How do I test the other wire? (Sorry, I do not remember the colors because I did the test a few days ago) I would like to complete the test before I try to sort through all the wires.

I am trying to get this fixed because the computer is not reading the temp. I am still getting code 21 that states the temp sensor is out of range.

I do appreciate your feedback and your patience. I do most of my own work but I have never owned a ford ranger 2.9 before. I am trying to learn my way around this one.

Thank you again.
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Thursday, April 4th, 2019 AT 1:36 PM (Merged)
Tiny
HMAC300
  • MECHANIC
  • 48,606 POSTS
The one wire that is getting voltage if grounded out will make the gauge go up to hot. If it'snot moving it may be the ground wire is the problem. I gave the color codes in one of the replies already so check the one going to the gauge. It can be a bad connection as well that is why I sent a pic of connector to temp sender. The code 21may be from the ect however so check connections at pcm and ect due to age of truck.
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Thursday, April 4th, 2019 AT 1:36 PM (Merged)
Tiny
RHAMILTON33
  • MEMBER
  • 1 POST
  • 1999 FORD RANGER
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 295,000 MILES
Enter your question. Temp. Gauge not working on 1999 ford ranger 3.0 liter flexfuel. Replaced both heat sensors and thermistat. Have heat inside truck. What else coulod it be?
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Thursday, April 4th, 2019 AT 1:36 PM (Merged)
Tiny
MHPAUTOS
  • MECHANIC
  • 31,938 POSTS
Earth the temp gauge wire to earth, the gauge should go full deflection, if not it will be a wiring or faulty gauge problem.

Mark (mhpautos)
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Thursday, April 4th, 2019 AT 1:36 PM (Merged)
Tiny
2CP-ARCHIVES
  • MEMBER
  • 4,544 POSTS
  • 1994 FORD RANGER
Just brought a 1994 Ford ranger. Both the fuel gage and the temperature gage don't work. How can I fix this?
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Thursday, April 4th, 2019 AT 1:36 PM (Merged)
Tiny
DRCRANKNWRENCH
  • MECHANIC
  • 3,380 POSTS
Their on a cicuit board so you will have to get the board, not necessarily the gauges themselves, from a salvage yard and replace it.
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Thursday, April 4th, 2019 AT 1:36 PM (Merged)
Tiny
WALTTIMM
  • MEMBER
  • 1 POST
  • 1997 FORD RANGER
  • 6 CYL
  • 4WD
  • AUTOMATIC
  • 93,000 MILES
The water temperature guage on my 1997 4.0L Ranger doesn't work.

I thought it was the sending unit, which I BELIEVE is about centrally located on the manifold but when I replaced it, there was no change.

I was told it could be the temperature switch. I am not familiar with this but I see a sensor/sending unit which looks just like it but on the left hand side of the manifold, to the right of the unit I replaced.

Is there a difference, please?

Thank you!
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Thursday, April 4th, 2019 AT 1:37 PM (Merged)
Tiny
DAVE H
  • MECHANIC
  • 13,383 POSTS
The "sender" inputs signal to the guage. The sensor inputs signals to PCM and fans

Engine Coolant Temperature (ECT) Sender (2.3L)On left rear of engine, below oil pressure sender.
Engine Coolant Temperature (ECT) Sender (3.0L)On top right of engine, near thermostat housing.
Engine Coolant Temperature (ECT) Sender (4.0L)On top left front of engine.

Engine Coolant Temperature (ECT) Sensor (2.3L)On top right front of engine, in water outlet tube.
Engine Coolant Temperature (ECT) Sensor (3.0L)On top front of engine.
Engine Coolant Temperature (ECT) Sensor (4.0L)On top front of engine.
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Thursday, April 4th, 2019 AT 1:37 PM (Merged)

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