99' Voltage draw
Elder User
Joined: Dec 2007
Posts: 784
Likes: 1
From: White Rock BC Canaduh
Have you scanned for codes? I'm thinking (possibly) if there is an issue with one of the parts that the fuse controls it may be something that might throw you a code.
It sounds like it's almost time to start tracing and searching. At least you found the circuit which is a very good starting point.
RE: The number 15 is the GEM, PCM, ABS Module, Brake shift interlock and the speed control
It's only a starting point and I'm only pulling this out of my butt, but the GEM might be a good place to start. They are well known to cause electrical issues after getting wet from even minor leaks at the windshield and other strange places hidden on these trucks.
Rick...
It sounds like it's almost time to start tracing and searching. At least you found the circuit which is a very good starting point.
RE: The number 15 is the GEM, PCM, ABS Module, Brake shift interlock and the speed control
It's only a starting point and I'm only pulling this out of my butt, but the GEM might be a good place to start. They are well known to cause electrical issues after getting wet from even minor leaks at the windshield and other strange places hidden on these trucks.
Rick...
Elder User
Joined: Dec 2007
Posts: 784
Likes: 1
From: White Rock BC Canaduh
[*]
That code is etched into my brain.
That will be the VSS on the rear differential.
That would be odd if it was the cause of the power drain, but may as well pop in a new one. Maybe it's shorting somewhere along the wires or the unit itself it fried and shorting.
Just in case you haven't had to deal with a VSS in the past and maybe save you a bit of searching,,, here's a photo for you.
The part in question (the VSS) is ontop of the rear differential.
I've had this photo on standby for awhile now and I'm pleased I can finally use it.
Rick...
That will be the VSS on the rear differential.
That would be odd if it was the cause of the power drain, but may as well pop in a new one. Maybe it's shorting somewhere along the wires or the unit itself it fried and shorting.
Just in case you haven't had to deal with a VSS in the past and maybe save you a bit of searching,,, here's a photo for you.
The part in question (the VSS) is ontop of the rear differential.
I've had this photo on standby for awhile now and I'm pleased I can finally use it.
Rick...
Elder User
Joined: Nov 2008
Posts: 668
Likes: 6
From: Northfield, MI
Idaho,
Glad you made some progress.
Based on what you said, I think the fuse you pulled is in the interior panel? The wiring manual shows that feeding two pins of the GEM and a circuit through the brake pedal position switch. The switch then feeds the shift lock actuator, and inputs to the GEM, PCM, and ABS modules. The pedal switch is easy to disconnect, so try that first if you haven't already.
The GEM connection is only shown as a "BATT" connection, which means it is only supplying battery power to the GEM and the power is not used on specific circuits. If you disconnect the brake switch and the draw remains, most likely the GEM is faulty like Rick said. We do replace them for issues like this all the time, but they aren't cheap, and the only way to diagnose them in this case is to eliminate everything else as the cause of the draw.
I'm leery of telling you to just replace it, as I would have checked and disconnected many other circuits if I was there working on it myself, but this isn't practical for you to do.
If you can find someone with a truck very similar to yours, you could temporarily swap them. They aren't that hard to take out.
Glad you made some progress.
Based on what you said, I think the fuse you pulled is in the interior panel? The wiring manual shows that feeding two pins of the GEM and a circuit through the brake pedal position switch. The switch then feeds the shift lock actuator, and inputs to the GEM, PCM, and ABS modules. The pedal switch is easy to disconnect, so try that first if you haven't already.
The GEM connection is only shown as a "BATT" connection, which means it is only supplying battery power to the GEM and the power is not used on specific circuits. If you disconnect the brake switch and the draw remains, most likely the GEM is faulty like Rick said. We do replace them for issues like this all the time, but they aren't cheap, and the only way to diagnose them in this case is to eliminate everything else as the cause of the draw.
I'm leery of telling you to just replace it, as I would have checked and disconnected many other circuits if I was there working on it myself, but this isn't practical for you to do.
If you can find someone with a truck very similar to yours, you could temporarily swap them. They aren't that hard to take out.
Thread Starter
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Freshman User
Joined: Oct 2005
Posts: 37
Likes: 0
FireMe, I pulled every fuse in the truck, both on the interior panel and engine bay. The only other two that dropped my amp draw were in the engine bay, Number 29 which is for the radio, so that makes sense.
And the number 27 which is the injector driver module, on this one it dropped from 115MA to 97MA.
And yes the number 15 that dropped me down to 35MA is in the interior panel.
I did disconnect the brake switch and had no luck there.
I will do a search on removing the GEM and see where that leads.
And the number 27 which is the injector driver module, on this one it dropped from 115MA to 97MA.
And yes the number 15 that dropped me down to 35MA is in the interior panel.
I did disconnect the brake switch and had no luck there.
I will do a search on removing the GEM and see where that leads.
Junior User
Joined: Nov 2010
Posts: 62
Likes: 0
I am trying to deal with the same problem right now. I have a draw of .18 amps and when I pull fuse 15 it drops to .01-.02. I pulled the brake switch...nothing, I replaced the GEM nothing. I still get the .18 draw. Does this feed the GEM only or does the power enter the GEM here and also leave for other circuits?
Junior User
Joined: Nov 2010
Posts: 62
Likes: 0
Update:
So...let me give the whole story. When i got the truck the previous owner pulled the relay and bulbs for the interior lights....I put them all back in and found that sometimes when the passenger door was operated, it would act as if the door was never shut.....I did some research online back then (about a year ago) and from what I figured, coupled with the parasitic draw and 'known' problems with GEMs in general that it was my GEM. Hence the replacement....
I hate when the obvious stares me in the face and I ignore it.
After thinking about it, I pulled the door panel off and disconnected the passenger door switch....the drain was now gone...
It appeared the problem was that latch the whole time.
Now this whole time (for the past hour or more) the truck was thinking the doors where closed and locked. I had closed each latch on each door and locked each door, but the door was physically open so I could access the compartment.
My best guess is the faulty switch is either shorting and causing power to leave the GEM through the circuit that signals for the door being open or closed, or it things the door is open and won't let the GEM go into sleep mode...
So...let me give the whole story. When i got the truck the previous owner pulled the relay and bulbs for the interior lights....I put them all back in and found that sometimes when the passenger door was operated, it would act as if the door was never shut.....I did some research online back then (about a year ago) and from what I figured, coupled with the parasitic draw and 'known' problems with GEMs in general that it was my GEM. Hence the replacement....
I hate when the obvious stares me in the face and I ignore it.
After thinking about it, I pulled the door panel off and disconnected the passenger door switch....the drain was now gone...
It appeared the problem was that latch the whole time.
Now this whole time (for the past hour or more) the truck was thinking the doors where closed and locked. I had closed each latch on each door and locked each door, but the door was physically open so I could access the compartment.
My best guess is the faulty switch is either shorting and causing power to leave the GEM through the circuit that signals for the door being open or closed, or it things the door is open and won't let the GEM go into sleep mode...
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