Originally Posted by rdodger
so far this winter i have gotten a jump 4 times and its everytime i didnt plug in the truck . when i go out it turns over but will not catch and as soon as i attach cables to the battery it fires right up . i did the simple multimeter battery test and it showed 12.8v on both batteries . tested my FICM and it was 51 v before and after starting . i was trying to figure out how to test the glow plug control module but didnt find any info . i also changed my fuel filters and oil a little early to see if it would help and it did not . is there anything i could try myself ? any input is greatly appreciated .
But this doesn't tell you anything about the amperage output of the batteries, nor does it tell you anything about voltage drops in the starter circuit. Step #1 is to have both batteries load tested individually, which can be done at any shop for minimal labour. For what it's worth, any diesel truck that rolls onto my doorstep gets BOTH batteries quoted as needed if either only one is weak. They are originally equipped with 750 CCA batteries each. I always push for 850 CCA units. As far as testing the glow plug control system, simply unplug each four way connector to each bank of cylinders and check each wire (harness end to glow plugs), between the wire and ground. Each should indicate between 0.5 to 2.0 ohms. If you get any higher readings than that, either the glow plug and/or the wiring (a. k. a. glow plug buss bar) is faulty. The next step if you were to get any higher readings than that, is to unplug the suspect glow plug and check between the top of the plug to ground. If higher than 2.0 ohms, the glow plug needs tobe replaced. For what it's worth, if there are any issues with the glow plugs or its control system, codes would be set/stored. If you have no codes pertaining to the glow plug control system, chances are there aren't any issues with them.