Desperado

What would cause the grid heater (wait to start light) to cycle in 80+* heat, while driving down the road at opperating temp, this just started to happen on my dad's 1991 last week while they were on vacation (happened around 5 times). Most of the time, even in the winter it does not come on, any help would be great. Thanks

97catintenn

a wire connector came undone on the drivers side of the engine. now the sensor doesn't know the outside temp. I think it's the one above or close to the fuel filter.

edit: Did you say it cycles while you are driving down the road? I've never heard of that one. I thought you were just talking about start ups.

BearKiller

In amongst all the wires that are on the HOT battery post are two identicle wires, about 8AWG, that power the grid-heater relays.

Unhook those two wires and problem gone.

Four Cummins trucks in the yard, grid-heaters dis-abled on all of them, no trouble starting in the coldest of times, and I do venture North and West in the winter.

Free89W350

My trucks a 89 and that light has been blinking since sometime in 93. My uncle never worried about it and it starts just fine, the only thing that bugs me about it is that at night I can see my lights flicker a little bit with the WTS light.

Ryan

wannadiesel

If it's a non-intercooled truck that means that the temp sensor is unplugged (or there's an open in the circuit).

Power Ram 250 C

If you can't figure out what the problem is just unplug the grid heater solenoid wires (4 very small wires with plugs on ends) and in place of the unplugged wires run a wire coming from a manual push button switch to them. That's what I did to mine because mine didn't cycle when they were suppost to be cycling. That way they won't be kicking on at temps from about 30-50 degrees.