My 1996 F-150 with the 6 cyl 4.9 engine has a problem with the coolant gauge. The gauge needle rests just below the "C" but when the other gauges "kick in" after the engine starts it goes backward all the way to the peg and never moves from that spot as long and the engine is running. I took the instrument cluster out (a real adventure) and checked the gauge by jumpering a 1.5 volt battery to the contacts. The gauge works fine. It goes all the way left or right depending on how the 1.5 volt battery is jumpered to it. The coolant sensor, located just above the water pump, reads about 36 kilohms with the engine cold and about 2.6 kilohms with the engine hot so it seems to be functioning OK. Disconnecting the sensor while the engine is running produces a "fluttering" sound from somewhere on the engine and goes away when the sensor is reconnected so it seems to be connecting with the electronics with no problem. Is there another sensor somewhere on the engine that I am missing or is it something else altogether?? I realize that the Ford gauges leave something to be desired but it just bugs the dickens out of me to see that particular one not functioning. Any help from out there would be appreciated.

 

the sensor for the coolant temp is mounted to the intake manifold
on the left hand side about 3 inches from the front edge
of the manifold
this will be just above the #5 cylinder
should be only one wire going to this sensor

 

Thank you for the reply. I guess I should have said that the engine is an inline six and not a V six. I just might have found the sensor though. It looks like it's located just below the number five cylinder and near where the oil dipstick tube is.

 

Nope, that's your oil sending unit. Look on opposite side of block same location & you'll see your temp. sending unit.

 

nope
I should have read the post a little closer

 

Thanks for the replys. I found the sensor and it checks OK. Had my wife turn on the gauges while I quickly grounded the wire going to the sensor and had no response on the gauge. Looks like there is a wiring or connection problem somewhere. Any recommendations for an after market/under the dash meter of some kind?

 

I got a 3 gauge group it had temp, oil, & volts made by sun for 29.00 at auto zone.

 

I hooked a wiring toner (we use these to trace data wires in buildings) to the sensor end and traced the signal through the harness and past the firewall into the cab. It looks like the connections are fine. I noticed some diodes tacked onto the flexible wiring sheets on the back of the instrument cluster when I had it out. Is there a schematic of the instrument cluster available anywhere?? Can't find one in the Haynes manual. Still trying to get the gauge to function.

 

I have had problems with the diaodes. Last week I had 6 clusters or 94-95 and all were different on back some had a diaode on charge the other on something else . I dont think thereis a set lay out it goes by time made. Good luck