Tachometer Problems

[datkinsonsr]

I hope you all had a wonderful Thanksgiving! My tach quit working. I Knew the sensor was leaking oil around the wires and tach was barely indicating until engine got up to temps. Then tach quit altogether. so I replaced tach sensor with new Ford P/N. Still doesn't work. Checked the fuses, all ok. Pulled Tach and inserted a gasser tack I have, still no work. Made sure all the plug connections are good. Also, I now only have 2nd and 3rd gear working on my E4OD since this happened. Up until a couple of days ago, everything was working very well. No issues. I don't know if this is related, but a couple of weeks ago, I had the tranny pulled to fix some leaks and a new flex plate installed. When I picked up the truck, it didn't want to move in drive. Placed into low gear and would move like it was in second gear. The shop replaced the gear position sensor on the side of the tranny and it seemed to work ok. At that time, I did not notice if the tach was working. Any help will be greatly appreciated.

MERRY CHRISTMAS TO ALL!

 

[OLDBULL8]

Are you sure there isn't a fuse blown, or just the fuse panel contacts are loose? Check fuse #18.

 

[icanfixall]

Best I can suggest is check the relay that is located between the wiper washer fluid container. It will be the brown relay. Someone has the testing procedures for this. I had lost me tach too a few months ago. Finally found the relay was not receiving the constant 12 volts power. Finally found the problem. It was a bad wire repair between the passenger side battery and the fender. Seems all the front end wires go thru that area. Mine had been repaired once before I purchased the truck in 96 so you know it was a long time ago. You must cut open the harness to find the bad wire if the relay is not getting power. In the harness there is all the fuseable links. Might be yours has failed to but this imply s you have no power to the relay. Any easy test is to make a jumper wire from the positive battery on the drivers side and connect it to the 12 volts hot all the time wire that feeds the relay. Then if the tach works you will know the relay is not receiving power. Not very often does the relay fail but that too is possible. They cost around 20 bucks but please test the feew wire before throwing parts at it. Also can someone here please post up the relay test.
Think I may have found the relay test.
http://easyautodiagnostics.com/ford/4.9L-5.0L-5.8L/eec-power-relay-tests-3#4

 

[datkinsonsr]

I will check this out tomorrow. Thanks. Will get back to you.

 

[datkinsonsr]

Tach Problem Followup

Best I can suggest is check the relay that is located between the wiper washer fluid container. It will be the brown relay. Someone has the testing procedures for this. I had lost me tach too a few months ago. Finally found the relay was not receiving the constant 12 volts power. Finally found the problem. It was a bad wire repair between the passenger side battery and the fender. Seems all the front end wires go thru that area. Mine had been repaired once before I purchased the truck in 96 so you know it was a long time ago. You must cut open the harness to find the bad wire if the relay is not getting power. In the harness there is all the fuseable links. Might be yours has failed to but this imply s you have no power to the relay. Any easy test is to make a jumper wire from the positive battery on the drivers side and connect it to the 12 volts hot all the time wire that feeds the relay. Then if the tach works you will know the relay is not receiving power. Not very often does the relay fail but that too is possible. They cost around 20 bucks but please test the feew wire before throwing parts at it. Also can someone here please post up the relay test. Think I may have found the relay test.http://easyautodiagnostics.com/ford/4.9L-5.0L-5.8L/eec-power-relay-tests-3#4

Many thanks to you for your help. Fuses rechecked ok. Apparently when I was checking the relay, I disturbed the connections enough to bring it back to life. All is working well now.