ECM problem?
 

I was checking out my Wait to Start light problems, and voltage checked the 2 leads (Orange striped and Yellow striped) that activate the Grid Heater solenoids, (they come from the ECM).

They are supposed to be 0 volts when the Ign. is off and 12V when Wait to Start light is on.

Mine are 4.3 volts when off and come up to 6.3 when the Ign is on.

Couple of questions.........

Can anything other than the ECM cause this incorrect voltage?????

How can the ECM be checked out?????

I have the same thing going with my 98.5 but my truck will not start. When I turn the key on the gauges do not work and the batteries will die in a day and a half if I leave the cables connected. I installed new batteries one at a time and that's when the trouble started. Can anyone help?

Grouds grounds grounds your grid heaters are very easy to get bad grounds the pump out around 190 amps when on and if there loose they will drain a battery quick check on the intake horn,the nut on the heater itself then trace cables from heater up to the fuse box on fender and then clean you terminalsal,connectors

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Radioman have you done the gauge test yet ...where you hold in the button on the cluster for 10 seconds the turn key to ...on ?????

Thanks for the suggestion lilmike, tried it several times and nothing changed. May need to tow this 6000 lb boat anchor to the local Dodge mechanic. As I don't drive this truck daily I can let it set for awhile. All info is appreciated. Rick

Does the truck try to start ...like the starter making noise and do your lights work ..did you leave something on like a light or somthin like that i have done that more then i care to admit lol i have herd that some times with these trucks the ecm can get zaped when the batteries get swaped but it is rare do you have a tuner that you can hook up to the obd2 port ?

Hi lilmike, After changing the batteries the motor will spin as normal but not start. The truck gives no indication on trying to start. The 40 amp fuse to Fuel Heater Diesel keeps blowing. No power to lift pump. The fuel and volt gauge does not work. I cant tell about the oil pressure and temp gauge. There is 5 to 8 volts on each of the 2 leads at the heater relays with the switch off. The manifold heater relays are not stuck. Does this help any? Thanks for your help.

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Sorry, don't have a tuner, may have to buy one. The heater checked out OK. When I connect the battery cable there is small sparks. Continues to kill batteries if left connected. Rick