I have a 1988 F-150 with a temp gauge that doesn't function. I replaced one temp sensor on the heater core line by the water pump but the gauge still is not moving. Is there a second sensor for the gauge? Somebody please let me know.

 

There is another sensor on the rear passenger side of the block directly beneath the Lower Intake Manafold.

Temp Sensor Location

This pic should help.

 

thanks for that pic it helps a lot. I suppose that I need to drain the coolant for that to work properly? No big deal if I have to I just hate refilling cooling systems.

 

To be honest, I am not sure. I would assume it's in the water jacket, and will spill out if you remove the sensor. I would drain it and fill with new anyway, it's a cheap maintenance item in my opinion.

 

THANKS FOR THE HELP I AM GOING TO SWITCH IT THIS WEEKEND. ALSO DO YOU KNOW BY CHANCE IF EACH FUEL TANK RUNS OF SEPERATE SENORS BECUASE MY FRONT TANK HAS A LEAK AND MY REAR GAUGE IS EITHER FULL OF EMPTY THERE IS ABOUT TWO SECOND OF BOBBING IN BETWEEN E AND F BEFORE IT LETS YOU KNOW "OH BY THE WAY YOUR OUT OF GAS"

JUST AN AFTER THOUGHT THANKS.

 

Each tank has it's own sending unit that feeds through the switch on the dash. I did alot of research into this because I designed a circuit that has a red/green led next to each end if the switch, if the tank is below 15% it shows red. I wanted something to remind me when the tank I am not using is empty so I remember to fill it before I need it.

But short answer, 2 sending units, check the contacts and the switch first however, it's the cheeper option if all it is, is a loose wire(s).

 

The temp sender on the side of the block will leak antifreeze when removed. It is difficult to get at. I was told to be careful when installing the new one so that the threads made good contact with the block.

 

By good contact do you mean for a ground or don't strip the threads? I was looking for the sensor yesterday and I have no clue how I will have to contort my self under the hood to get at that thing. Thank you Ford for a great position.

 

I got under my truck and removed mine. Its a 4x4 also so the space was a bit tough, but it worked.

To be honest i forgot how i got the dang thing off, but it wasn't too difficult...

The coolant sensor is in a water jacket, it'll start pooring out when you take it off. I just sort of swapped fast and put some more coolant in there. Not such a great idea though... thats just asking for an air pocket

The one you replaced is for the ECM temperature sensor, so its not gunna help your gauge..

 

Thanks for the advice I plan on doing it tomorrow so I will post how it went.

Thanks again

 

Thread contact for an electrical ground is my assumption. I recall testing it with an ohmn meter.

 

I used a very long extension with a universal joint and ratchet. I think that I also disconnected the battery ground as it required working close to the starter connections.

 

Turned out to be fairly easy. I just laid down on the motor with my feet on the driverside and reached down with a wrench. I ended up not getting a bubble or a crossthread. Lost maybe a cup of coolant then just added in the resivior. The truck runs at the "O" in NORMAL. I also found that the line that goes from behind my first cat had the smog pump line disconnected (that would explain the headaches I was getting) so I reconnected that. Now the only other thing I have to do is fix the leak in th front tank and the sending units. The rest that is wrong with the truck is rust and there is no curing that on this one. But it runs strong. Thanks for the advice

Jordan