My truck is in the shop for the issue I had with it not starting. In the past, If I let my batteries get low, the truck would not stop cranking while trying to start and the wipers would go off on their own. This only happened after batts got low. turn the key off and it keep turning.THe mechanic can't even get it to turn over correctly as in turn off and on with ignitio switch to check things. each time he tries, it wo'nt shut off with key and he has to jump out and unhook battery cables. He thinks this issue is caused by this module. It's always happened with low battteries. Prior to talking it to him, i decided to give the new batteries a little charge since it has set for 4 months to prevent this happenening to him. He says he can't get it to stop. what is the function of this module and is he correct? I'm ready to go get it. also, when I tried to give them a little charge, my charger went bad and ruined my two 1 year old batteries. it now has two brand new 1000 CCA bateries in it off the shelf. I don't know.It's a 2000 7.3 superduty.

 

HELP!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

 

you may have a wet gem/fuse box. the cab marker lights leak over time and when it rains good and hard it seeps in between the bases and lenses, and into the lens screw hole. then it drips down the inside of the fixture and down the center of the light connector. then down the bend in the wire and drips onto the roof channel... from there the water follows gravity along the channel to the a frame and down it goes.. almost str8 to your wiring harness y to the gem and fuse box. you cant really take the fuse box apart with out destroying it... but you should be able to pull the cover off the gem and pull it out of the housing to look for moisture and/or burnt components.
sometimes it just takes a few days to dry and everything is hunky dory.
silicone did a good job resealing my marker lights.

you need to fully charge your batteries. if they are weak then no amount of jumping will get it started... you must have minimum required voltage while cranking for the injectors to fire. check battery voltage while cranking.
also... check starter selonoid and ignition switch.
it is easy to test the ignition switch. measure the ignition selonoid signal wire while having a helper turn the ignition switch over like trying to start it. when they release... if the start signal still shows hot on your meter... the circuit has an issue before the selonoid. if the signal drops off when they let go of the key then the switch is probably good, and the selonoid is sticking closed. replace it.

 

Chris is telling you some good info for your gem to keep it from getting wet. Silicone those lights under your headliner at your roofline.
Now to the problem at hand. Your starter continues to start/run even when the key is not in the start position. A few causes for this and I will list each item and then explain how to troubleshoot each one.
1. When you turn your key to start the starter motor relay mounted on the passenger side fender well wall can be sticking closed and not spring returning. This would be one of the common causes for the starter motor to continue to rotate with the key off. Using a multimeter that has been verified in the 12 volt range on your battery in the DC volts mode place the red lead on the small lead(closest to the top) on the starter motor relay located on the passenger side fender well and the other end on a good ground or the battery negative terminal. You will have to pull that connector off just a little bit to expose part of the terminal stud. It is a slip fit and is fairly tight so just give it a tug. Now have another person turn the key to the start position and look for about a 12 volt signal from that small wire I mentioned. There are only three terminals on the relay and it is the smallest one.
When you let off of the key and the key goes to the run position does the 12 volts go away from that wire? If the 12 volts stays on that small wire then your ignition switch that the key rotates is no good.
The signal from the key switch goes from the battery thru two fusible links to a 50 amp fuse in the battery junction box to the ignition switch thru the start pin to a 15 amp fuse in the central junction box under the steering wheel) to a clutch pedal position switch/position switch jumper to the transmission range sensor(park or neutral required) and then finally back up to the small terminal on the starter motor relay on the passenger side fender well. Be sure to push the small wire back on the stud fully.
The above should tell you if the ignition switch is sticking in the start position.
2. If the starter continues to start we need to look at the signal thru the Starter Motor Relay(SMR) at another point. The bottom large terminal on the SMR is always at battery voltage. Verify this by checking with your multimeter. Red lead on bottom terminal and black lead on the ground for the battery. Ok now you have verified that you have voltage on the bottom all the time. When the key is turned to the start position the SMR connects the Large terminal on the bottom of the relay to the Large terminal on the top of the SMR. So with the key off or in run you should have no voltage on the Large top terminal. Let's verify this now. Red lead on the Large terminal of the SMR and the black lead on the battery ground. You should not have any voltage. Keep the lead in place and have your handy dandy assistant turn the key to the start position and see if voltage shows up at the top terminal. Is the voltage there? If yes then have your assistant let go of the key and see if the voltage goes away. If the voltage stays after the key is turned back to run or off then the SMR is faulty and is sticking closed. Replace this relay if this is the problem. If this is not the problem then go to number 3.
3. INSIDE the starter motor/bendix there is a VERY LARGE RELAY that the SMR turns on when you turn your key to the start positon. That is where the 12 volts on that top terminal goes to when the key is in the start position. The voltage flows from the battery thru the SMR out the top terminal to the STARTER COIL inside the starter and pulls in a VERY LARGE CONTACT that turns over the starter motor. If the power to the top terminal on the SMR turns off when the key goes to the run or off position and the starter continues to turn then the Starter if faulty and it is gonna cost you about 200$ for a new starter. Darn starter
Now I hope I was as detailed as I could be to help you out. I hope you click on my reps heart on my post and give me some digital love. My fingers are tired and I need to go to sleep as I am currently on nights.
Dwayne

 

aw c'mon Dwayne!

i said the same stuff you said i just went the short route and implemented my firm grasp of bad engrish jibber speek.

 

Good Lawd you guys are great. I'll investigate all this and get back to you fellas over the holidays. I do know this, the mechanic changed the starter relay on the firewall and it didnt help. He took the starter off the truck and with a jumpers box, he said it was ingaging in and out fine. This starter is over a year old but not much more.

 

I had a few extra minutes before bed this morning so I did what the ex Navy Nuclear Electrician in me would do. Details, Details, Details. It is all good. I hope your turbo is still running strong Chris. Let me know if you need some more Harbor Freight coupons and I will send them your way.

In edit I say take that starter since it is out and have it tested at your favorite Auto parts store or the store you purchased it from.

 

Did somebody say Harbor Freight coupons??? Here ya go: New Harbor Freight Tools coupon! (not really just too funny) (Page 1)

 

Lets just hope it isnt the GEM because they are almost impossible to get one for these trucks. I had issues similar. Ended up being a leaky windshield/visor, getting water into my fuse panel. GEM is connected to fuse box, but it was bone dry. fuse connectors had some corrosion and that was the issue. The closest GEM was in the Virgin Islands and they werent even sure if they could get it out. Would have to be a junkyard find

 

I just want to be clear here. That gem is not involved with the starting circuit at all. All of the starting components are exterior to the gem and do not go thru the gem.

 

Well, he finally got past the starting issue. He first fund out the GP relay was bad and none of the glow plugs have been working hence the need to have it plugged up to start. The ICP was reading 1800 all the time and would not allow it to start. Now tat it is running, next is to address the smoking and missing at idle. He got bad reads on thenumber 7 cylinder and will o anoter test in the am. I have known it's had a bad injector for a good while but got bad and began to miss. He said his cost of injector is about 300 out of Nashville Tennessee. So, maybe I'll get it back someday.