Electrical Gremlins

[JKellis]

Well the dreaded gremlins finally found their way into my truck. The other day the CEL came on while driving home, truck ran fine all the way home. The next morning I plugged in the scanner and scanned the PCM and ECM, no codes stored or pending. Cranked the truck and no CEL. I drove the truck the next day and here comes the CEL and the tach is reading 0 rpm. Truck running fine. Get home, plug in scanner and still no codes. So I order a Crankshaft Position Sensor from Geno's (great people by the way.) The next day I drive the truck, tach works, no CEL, but my Wait to Start light will not light when I start the truck. Scan again and still no codes. Truck starts and runs fine. Today I disconnected the batteries, pulled the starter and changed the CPS. Put everything back together and now I have WTS light, grid heaters are cycling, truck starts and no CEL. I tested my alternator for AC voltage and after jumping around like crazy, the meter finally settled on 0.02 volts. I plan to find somebody that can load test the batteries. Other than that, I am at a loss. Any suggestion would be appreciated.

 

[W. J. Turney]

Well the dreaded gremlins finally found their way into my truck. The other day the CEL came on while driving home, truck ran fine all the way home. The next morning I plugged in the scanner and scanned the PCM and ECM, no codes stored or pending. Cranked the truck and no CEL. I drove the truck the next day and here comes the CEL and the tach is reading 0 rpm. Truck running fine. Get home, plug in scanner and still no codes. So I order a Crankshaft Position Sensor from Geno's (great people by the way.) The next day I drive the truck, tach works, no CEL, but my Wait to Start light will not light when I start the truck. Scan again and still no codes. Truck starts and runs fine. Today I disconnected the batteries, pulled the starter and changed the CPS. Put everything back together and now I have WTS light, grid heaters are cycling, truck starts and no CEL. I tested my alternator for AC voltage and after jumping around like crazy, the meter finally settled on 0.02 volts. I plan to find somebody that can load test the batteries. Other than that, I am at a loss. Any suggestion would be appreciated.

Any luck with your gremlins?

 

[JKellis]

Any luck with your gremlins?

I eventually put new brushes in the alternator. No problems since.

 

[SAndreasen]

My whole truck has been eaten by gremlins

 

[DavidC]

JKellis, how many miles were on the truck when you installed new brushes ?

 

[JKellis]

JKellis, how many miles were on the truck when you installed new brushes ?

130,000

 

[Vaughn MacKenzie]

Another problem that can cause electrical gremlins is a shorted diode in the alternator. That caused erratic torque converter lockup issues on my truck.

 

[Wiredawg]

I would like to make a proposal to help eliminate electrical gremlins: Methodically go through every electrical connector, open them, inspect for corrosion (white, green, black powder), clean if found with connector cleaning tools (avail at most auto, electrical stores), apply dielectric grease, and close back up. Locate all the grounding points (often the source of gremlins), remove the bolt/screw holding connector(s), clean the metal on the truck with wire brush, clean the connectors and the bolt/screw, apply all with dielectric grease, and replace as found. Use EXTREME care on the ECM separating the conenctors and remove it, as I believe (pretty sure) it gets its ground through the housing from the engine.

I ALWAYS purchase a FSM w/ wiring diagrams and connector locations... makes doing electrical maintanence and trouble shooting WAY easier.

Even on my 2017, any time I open a connector, I inspect and apply dielectric grease. At 5years, the whole truck get the treatment.

Anyhoo, this is what I do with ALL my equipment electrical connectors.

Cheers, Ron

 

[SAndreasen]

I would like to make a proposal to help eliminate electrical gremlins: Methodically go through every electrical connector, open them, inspect for corrosion (white, green, black powder), clean if found with connector cleaning tools (avail at most auto, electrical stores), apply dielectric grease, and close back up. Locate all the grounding points (often the source of gremlins), remove the bolt/screw holding connector(s), clean the metal on the truck with wire brush, clean the connectors and the bolt/screw, apply all with dielectric grease, and replace as found. Use EXTREME care on the ECM separating the conenctors and remove it, as I believe (pretty sure) it gets its ground through the housing from the engine.

I ALWAYS purchase a FSM w/ wiring diagrams and connector locations... makes doing electrical maintanence and trouble shooting WAY easier.

Even on my 2017, any time I open a connector, I inspect and apply dielectric grease. At 5years, the whole truck get the treatment.

Anyhoo, this is what I do with ALL my equipment electrical connectors.

Cheers, Ron

Good idea