WTS light not coming on/no grid heater

9

99GreenCummins

That guy....
Joined
Feb 15, 2011
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Grid heater will not cycle at all when you go to start the truck. They work just fine when truck starts. They will cycle as usual.

What would cause this? Just replaced relay, checked solenoids on fenders. Is it my ecm? It had similar issues 2 years ago and it was early signs of an ecm failure I think.
 
Last one I ran into like that was the ECM. Only difference was, when the light came on it started, if the light didn't come on it would just crank.
 
From what I've read it points to the ECM. But before I would go down that road I would make sure all battery connections are clean. Batteries tested good, and all grounds inspected, cleaned, tightened. I'd reseat and inspect the EMC termination as well.

I'm methodical in my troubleshooting so I would only work one piece at a time and test the results. I always want to know exactly what caused the issue.
 
My buddy's truck did this, and it was a failing ecm. but the lift pump circuit was also going out on his.
 
I just cleaned all the grounds, all connections, batteries tested good about a month ago when I had another issue. I removed ecm and cleaned grounds and added dielectric grease to ecm connection. Going to see what happens in the am. Doubt it changed anything.


Anyone have an ecm for a 99 manual?
 
Only reliable ECM's I know of are from the dealer. Make sure your alternator is putting out clean power. It won't fix your existing issue, but will help ensure you don't repeat it anytime soon.
 
Shainer said:
Only reliable ECM's I know of are from the dealer. Make sure your alternator is putting out clean power. It won't fix your existing issue, but will help ensure you don't repeat it anytime soon.
Click to expand...

What do you mean clean power?
 
What does the ECM use to dictate the grid heater, coolant temp and inlet temp?
If it's like other platforms, you could have one of those two sensors failed within range and there be no outward sign of failure, just the symptom you have.
 
The WTS light should come on immediately, as do the other dash lights. A sensor failing should not delay the light check sequence at all.

Ed
 
Yankneck i correct. You can disconnect all sensors and WTS will still comme on instantly. Lag of the WTS light is a sign of bad RAM in the ECM and the software isn't booting up in a timely manner.
 
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