JohnnyGillette

1994 F150 302
I replaced the thermostat, and the sensor next to the housing but still no luck. This truck has been running "cold" on the gauge since I bought it 5 months ago. It runs better than it did when I bought it. Did minor tune up spark plugs and wires replaced, o2 sensor, cap rotor, egr. But the worry is with this dang coolant temp. It barely goes to normal on gauge.
Any other sensors...or ideas?

Thanks in advance
JohnnyGillette

Ranger2F150

Have you taken the radiator cap off "while cool" and watched the water flow as it warms up?
You could have a water pump going bad or a clogged raditor.

tailgatefisher

If you already replaced the sensor and the thermostat than there is either a bad connection within the wires to the sensor which can easily be tested with a voltimeter or the gauge itself may not be working correctly in behind the cluster panel.

Mevans24

I'm having the same problem... temp gauge wont move

transmaster

Here is the test series for your temperature guage.

If you happen to need a replacement gauge go here:
http://www.lmctruck.com/icatalog/fd/full.aspx?Page=43

C2-Verify power at instrument panel.

C3-Measure ECT sensor circuit 640 continuity.

C4-Check gauge cold calibration.

C5-Check gauge hot calibration.

C6-Check ground connection.

C7-Check flex circuit continuity.

C8-Check for corrosion / poor connections.

JohnnyGillette

Tomorrow I will check the wiring, take off cap and look for flow. I'm a college student so I've been working on papers tonight, or I'd go now. I will post my findings.

If the pump was going out, wouldn't it read hot? Nothing is coming from the weep hole on the pump. Of course if the gauge isn't working then it may not read hot. It goes up after idle or drive for a bit, but it only goes up barely.

Thanks for the help so far, I will be calling on ya'll many times over the next few months. Next thing after the engine items are taken care of, I'm wanting to take out the auto hub 4x4 and install Warn manual. I wish it was a floor shift actually. I just had a transmission shop rebuild the tranny and "better" the stock AOD trans. This truck is going to last me and I plan on taking time and doing it right.

Thanks in advance
Johnny Gillette

Just call me Sean

iTrader: (1)

There are two separate temperature sensors, one for the computer and one for the gauge. On the V8 the one for the gauge is in the intake manifold near the bottom of the distributor. It is the single wire sensor. If the engine isn't warming up completely the computer will store an ECT code so you can check the codes to see if it isn't warming up. A bad radiator cap will also keep the engine from warming up.

transmaster

Here is a tech bulletin on your problem. It isn't likely you have the bad sender but you never know.

Article No. 95-13-2 07/03/95

GAUGE - TEMPERATURE-READS IN LOW RANGE - ERRATIC READINGS SERVICE PARTS - RETURN OF OBSOLETE TEMPERATURE SENDERS

FORD: 1990-95 F-150-350 SERIES
1
Temperature Sender F1SZ-10884-A with a build date code prior to 2774 (277th day of 1994) should be purged from your inventory and returned to your facing PDC. These parts are being made obsolete because of an incorrect crimp during assembly. Installing these parts on a vehicle could result in early loss of temperature sender function.

ACTION:

Remove and return the suspect parts from your dealership's inventory. The obsolete parts should be withdrawn from your inventory and returned to your facing PDC within 30 days of this TSB. NOTE : USE TSB ARTICLE 93-24-8 FOR DIAGNOSIS PROCEDURE IN DETERMINING IF LOW GAUGE READINGS COULD BE ASSOCIATED WITH A TEMPERATURE SENDER CONCERN. 1. Perform 100% sort of all stock on hand. 2. Suspect stock has a build date code prior to 2774. Usable stock will have a build date code of 2774 or later. NOTE : DATE CODES ARE LOCATED ON THE SIDE OF THE SENDER HEX. 3. Usable stock can be returned to your inventory and released for normal sales. 4. Return suspect part (F1SZ-10884-A) to your facing PDC using the least expensive transportation. 5. If claim is processed electronically via DOES II, use return code "GB"; otherwise, complete a separate paper claim form FPS-340 using return code "J". 6. In the Remarks Section, write "Returned per TSB 95-13-2". LIMITS
^ The returns must be received within 30 days from the date of this TSB. ^ Returns are restricted to the subject parts. ^ The parts returned must have been purchased from FCSD in accordance with Policy and Procedure Bulletin 4000. CREDIT
Credit for parts and prepaid freight costs will be issued.
Replacement stock is available for ordering
PART NUMBER PART NAME

F1SZ-10884-A Temperature Sender OTHER APPLICABLE ARTICLES: 93-24-8
WARRANTY STATUS: INFORMATION ONLY
OASIS CODES: 203000, 203200, 204000, 204200, 402000

transmaster

If you need a wiring diagram I can supply that as well.

One more thing, I know you didn't do this but maybe a sweetie in painted on clothing wiggled by when you where installing the Thermostat and you got it in upside down. Hang in there you'll get it.

JohnnyGillette

My girlfriend had been out in the garage talking to me about something...I wasn't really listening, but I had paid enough attention to her that later I thought I may have put it in wrong..the thermostadt that is. Now this was while the housing was setting and I hadn't known about the temp still not working...it was just based on me thinking I had been distracted and may have messed up.

I checked..it was good. Thanks for looking out Transmaster.

Sean, Transmaster, and all else, thanks for the tips. I'll let you know tomorrow.

JohnnyGillette