Engine/Transmission (1998.5 - 2002) Question about intake heater

[Dixon]

I've noticed that my grid heater is not shutting off like it should. Instead of shutting down when I reach 20 mph it will stay on for 15-20 minutes. At least I think it's on cause my fuel pressure drops down to 7 or 8 on WOT instead of 10 to 11 like normal. What relay or sensor could be bad? Does that sound like the coolant temp sensor being bad. What really gets me is the intake heater is not coming on at all! I checked and it's not heating up and I still have to put up with the alternator drain for 20 minutes. Has anybody ever jumped straight to the grid heater with a hot wire just to see if a relay is bad? And if so do you need to power up both of the post? Thanks for the help on this. ben

 

[RBallard]

A few years ago, around the beginning of winter, I parked the truck at work and was inside for a couple hours. I came out to get something and thought someone had a coal stove going due to the smell. When it came time to go home about 4 hours after I had parked the truck, I hit my key fob to unlock the door but nothing happened. I opened the door and and really smelled the odor now. I put the key in the ignition and nothing happened. I realized the dome light wasn't on and everything was dead. I opened the hood, the intake horn which used to be a pretty gray was not black as night and too hot to touch. The wiring insulation, what was left, for the intake heaters was melted and charred. I got pretty hot under there! I had thought about wiring an indicating light to the contacts just so I could keep an eye on things. I don't believe mine cycle at all while I am driving, only when I start the truck and idle. I am not sure if this is an indication of faulty relays or not.

 

[darkhorse]

There are actually two seperate grid heaters each with it's own relay. The relays are attached to the left inner fender below the batterry. You should be able to check for 12 volts with a meter at the cable mounting studs just behind the itake air horn.