93-12Smoke

Since I bought my truck it seems to have something wrong with the grid heater. Up until now if its cold enough for them to turn on I have to quickly crank the truck. If I let the wait to start light turn off, usually 5-10 secs, and then let it cycle again my battery will be completely dead. Yesterday was a nice warm day and I stopped at a gas for a couple minutes. Came back out and the battery was dead. All I got was a click when I tried to start it.

Called the wife to come jump the truck off. Her truck is equipped with a high amp alternator, don't remember size and a 1000 cca battery I installed in December. I hooked my large home made cables up and when I turned the key on my truck on I heard the grid heaters cycle on but never go off. Truck would just barely turn over but not crank. The wife also informed me she could tell when I just turned my key on because all her lights would dim down, then even more when I would try to crank.

I assumed my battery was toast and went and got a new one, a 1400cca fleet series battery. Before installing it I disconnected the grids at the intake. Installed the battery and fired the truck up no problem.

I took the old battery in to be tested and they confirmed it was good and working properly.
My question is, is this a sign my grids have shorted out or the temp sensor is bad? I haven't reconnected the grids because I don't want to short my new battery.

I've made it 4 winters now without them so they aren't a real loss just trying to figure out if I may have a problem elsewhere.

j_martin

Grid heaters normally draw over 200 amps. A good 500 CCA battery probably wouldn't run them and start the truck. It would take at least a 225 amp alternator to keep up with them, so the indications when jumping is normal.

They should normally run about 10 - 15 seconds, then shut off until you cycle the key. After the engine starts, they will cycle on for short bursts until the engine is warm.

If the heaters were on all the time they would either catch fire, or kill the battery with the alternator going full tilt.

I suspect you are sending a boy (car battery) to do a man's job (start a truck)

Stock battery is 1000 CCA, group 31 case.

93-12Smoke

Negative, I've been running a large truck battery. This new battery is the next size larger amp wise. I am thinking the solenoids are stuck on which is what drained the battery and prevented it from being jumped off. My battery was so dead even the hood light was very dim. With the temp yesterday 65-70 the grids shouldn't have came on in the first place.

patdaly

Here is the fly in the ointment, if the solenoids were stuck, it would not matter if your key were on or off, they would be drawing it down right now if they didn't melt the wires first. I suspect something is telling them to come on, or you have a PCM issue telling them to come on when the PCM powers up.

Since they have the 12V applied, and your PCM drags them to ground to operate, I would probably just take the easy way out and remove the negatives from the small posts on the solenoids and rig up a push button to bring them in manually.