Electrical Problems with WTS and WIF when outside temp is cold...HELP????

[mattfultz]

I have a 93 D250 and when the outside temp is cold, the wait to start light and water in fuel light do not come on. The truck still starts and runs fine, but when you cannot go faster than about 55 because the transmission will not shift into 4th. Also the cruise control does not work during this time, and the voltmeter indicates no charge, and the AC pump will not work. After the engine warms up, sometimes, it will start clicking a relay under the hood. When the relay is clicking, the check engine light, the WIF, and WTS lights strt flashing very dimmly and then get brighter and brighter. The clicking slows and finally the realy closes and the voltage is restored to normal, the ac pump works and the transmission shifts from 3rd to 4th. If this is normal for this truck, then I am not happy! When this happens, If I allow the truck to idle for about 15 to 20 min to warm up, it then goes away. I replaced the relay that was clicking and still nothing changed, and I also replaced the battery. Nothing has changed. Does anyone have any idea's about what is going on, and if there is a sensor that is bad or if the drive train control module is bad? Also, sometimes after the system is back to normal and you decide to use the cruise control, setting it will cause the WTS light to flicker and if you hold it down for more than one second, the transmission will shift out of 4th into 3rd! It seems the colder it gets the worse the problem becomes. Can anyone help. Thanks to anyone who can help.

 

[jrjuday]

Matt: Check your ground connections. A bad ground can cause all kinds of wierd symptoms.

 

[Paychk]

Also pull the trouble codes from the computer, the engine speed sensor may be intermittent and causing your problems.

 

[cerberusiam]

Definitely check the grounds then start checking the wiring harness for the crank sensor. Clean all the connections well then grease with dielectric grease. Might want to check the fusable links and the wires feeding them from the battery also.



No that is not normal operation and there is definitely a problem.



I can still hit 75 with the OD locked out but thats another story.

 

[mattfultz]

I just checked all the sensors by just wiggling the wires and unplugging each one. When I came to the speed sensor on the tail end of the transmission, (the solenoid was clicking at this point) I unplugged it and the relay made a different sound. It, however, did not stop clicking, but it was the only sensor that had an effect. How is it possible that the outside temp would effect this sensor??? That is what boggles my mind! I checked the crank position sensor by unplugging it and wiggling the wires. I did take the transmission out of the truck about 2 months ago to replace the rear main seal set and the oil pan gasket. I never took that sensor out though, but it could be just going bad. Oh, I almost forgot, just yesterday, I jumped in to start the beast and the speedometer jumped to about 60 mph and the trip and odometer started spinning like crazy. It racked up about 30 miles in about 15 seconds and the truck was not even started!!!!!! This would obviously point at the speed sensor, but how would that effect the WTS and WIF and the check engine light?

 

[cerberusiam]

It sounds like you have a bad ground circuit or a shorted wire somewhere in the harness. The speed sensor does not provide a signal until the truck is moving so it will not affect speedo.



You need to remove all the grounding points under the hood and under the dash and scrape them down to bare metal to make sure they are good. Check your wiring harness that the speed sensor is part of to make sure there are no bad wires, pinched areas, etc. Since the relay is clicking when you work on the speed sensor try to isolate that section of the harness and see if that changes things.



Try this also, the large black wire on the positive battery cable powers all the accessories and such. Try moving it around in the clamp and see if makes things work. They will corrode inside and not make contact.