Why does the temperature gauge in my 91 Ford Ranger pickup not work? And
 

is it related to heater not working? The needle on the temp gauge does not move at all (always says cold). It has been this way since I purchased the truck about a month ago. The truck runs great. However, I would like to know if the engine is heating up -- it seems like the gauge might just be disconnected.

My other observation is that the heater is very weak. It only warms up after about 30 minutes and even then it's only luke warm. If the outside temperature is -10 or lower the air hardly gets warm at all.

Any info would be helpful, thanks!

One of two things. Either you don't have enough coolant in the system or your thermostat is stuck open, too cold of therm, or you just don't have one installed. Check fluid level first then just replace thermostat. Can buy one for less than ten bucks.

Replace the thermostat. A bad thermostat will cause the problems you describe,low temp. guage and lack of heat.It,s pretty easy to do and will fix your problem right up.

if your thermostate is stuck open, then your engine will take a long time to warm up, and the heater will probably not get all that warm.

if i remember correctly, the t-state is easy to get to on a four cylinder. if you have a v6 then it's almost as easy, just more stuff in the way.

good luck!

the coolant sensor is located next to the top radiator hose. disconnect the wire connector. take a jumper wire and connect one end to the coolant sensor wire connector. connect the other end of the jumper wire to ground. turn the key on and the gauge should move to the hot position. if it move to the hot position, replace the coolant sensor. if the gauge does not move to the hot position, replace the gauge inside the dash

Re: Why does the temperature gauge in my 91 Ford Ranger pickup not work? And
 

hey i tired this i disconnected it. Its a two wire connector and i must of did it wrong and i really dont have a proper jumper but is there a certain way that i place the jumper into the connector then do i ground it.. im sry im new to the ranger game and also is there anyway to test the temp sensor, ( the one wire sensor ). How do i know its not the temp sender. My problem is the temp gauge doesnt move at all and i have decent heat and also i tired taking the cluster off but i removed the brownish screws but it wiggle but it like the harness of something is holding it up.... p.s im thinking of just getting a aftermarket one i drive a 94 ranger 4 cyl 2.3 2wd all stock

Re: Why does the temperature gauge in my 91 Ford Ranger pickup not work? And
 

ok so i changed the temp sender the little one wire one and nothing still doesnt move.. what do you guys think i should change next... again i have good heat and also when i was driving today for about 20-30 mins the gauge very sloy moved it the end of the C but not to normal and even close

Re: Why does the temperature gauge in my 91 Ford Ranger pickup not work? And
 

If you changed the sender and it didn't change, I think you probably do have a thermostat stuck open. "you have good heat" is relative. There is warm and there blazing set your face on fire hot. After you've driven for a while, feel the upper hose, it should rock solid hard and very hot. See how it feels.

Re: Why does the temperature gauge in my 91 Ford Ranger pickup not work? And
 

ok my thing is the heat is good and the gauge today after about 1hr on and off driving and errands it climbed up to just below normal/ beginning of normal do u still think its the thermostat or the water pump and is there a d.i.y thread for either

Re: Why does the temperature gauge in my 91 Ford Ranger pickup not work? And
 

It should be in the middle of normal. I don't know what "the heat is good" means, so I'm ignoring that statement. I can't base anything off it, cause I don't know what it means. So yes, I think it is thermostat most likely still.

Re: Why does the temperature gauge in my 91 Ford Ranger pickup not work? And
 

ok do you have to change the whole housing? Do i have to pull the radiator out to get to it ,i see one bolt on top but i cant seems to see the other one

Re: Why does the temperature gauge in my 91 Ford Ranger pickup not work? And
 

Nope, just the stat itself. No pulling the radiator either. There should be three or four bolts. Not sure what it looks like on a 2.3 but often you have to remove the throttle body or something to get access to it.

Re: Why does the temperature gauge in my 91 Ford Ranger pickup not work? And
 

Hey Fire ranger, I have the same prob. My heat sucks and the guage is dead, but the motor seems to run cool enough. The book says there's 2 sensors. the one you are talking about is the one that controls the fuel mixture according to the water temp (the one in the front in the heater hose line near the top radiater hose). But the sending unit for the guage has a single lead and is located below the head, near the rear of the engine, drivers side.
I'm going to change mine tomorrow.

Re: Why does the temperature gauge in my 91 Ford Ranger pickup not work? And
 

i have changed both sensors and i have change the thermostat i think it must be my actual gauge in the dash is faulty

Re: Why does the temperature gauge in my 91 Ford Ranger pickup not work? And
 

If the heat is not blowing hot, it sounds like the gauge is reading correctly to me. Is the coolant full, and how old is your water pump? But this is the total opposite of the story you gave last month. So it's impossible to diagnose when you keep saying the opposite each time you work on something.