wow electrical.............
 

hey guys, man i have a good one for ya,i have a 99 f-350 dually,with a great 7.3,that runs like a raped ape.the problem is that when it rains for some reason,it wont start.(aka christine)when i turn the key on all the guages start bouncing around,and the dash lights go dim,then with the key off, the door locks start opening and closeing.i have all new batterys and alt,and starter. although in good weather it is fine,runs and starts right up.dazed and confused.can you guys help me out.would be greatly appreciated.:argh:

You have a short somewhere

Do you get water spots inside the cab?

electric problem
 

hey jamsmith,sorry what do you mean by water spots,havent seen any just on the outside of windshield......feels most under dash by computeron driver side..........and the batterys are both dead...........

if you’re getting water in the CPU AKA computer tron then there is your problem I’m betting. check all weather seals that pertain to and around the CPU. i bet that’s the issue.

Have you or anyone else ever had a windshield put in this truck? I have seen these get a leak started around the windshield and it will get them gem module wet. This will turn the interiopr lights on make all sort of electrical shorts appear and run the batteries down overnight. It is kinda a bitch to catch if you have not seen it before. The gem module should be on the hump under the dash if I remember right. I will look at mine tomorrow to make sure and post it for you ........ That is where I would look at first. Next time it rains pull up the carpet on both sides and feel for dampness

aka christine............
 

hey guys thanks again,the info is really helping,i will be trying the gem module next..thanks wmorrispilot,i will let you guys know what happens next.just bought another set of new batterys again.:argh:

You might just try to put a charge on the batteries. Try a charge and a load test. Save your money

If you have a seal issue around the windshield or any front cab leaks then the pillars will pour that water right on the gem unit and the interior fuse panel. See this thread:

https://www.dieselbombers.com/ford-p...al-issues.html

what is the GEM module?