Welcome Visitor! Please take a few seconds and cougar9150
New Member
- Joined
- Feb 4, 2011
- Messages
- 2
- Vehicle Year
- 1998
- Transmission
- Automatic
B4000 Electrical issues
I don't post here often but have run into some issues with my 98 B4000 Auto that I need help with. I recently had some charging issue and had to replace both the Alt and battery. I also crimped and soldered new ends onto all the cables also as they ends were previously pretty corroded.
The day I replaced the alt but before I replaced the battery I drove the truck home after installing a new alt from Adv Auto. I get home and the lights are flickering and my battery gauge is reading really low. I whip out the multimeter and check the voltage and I'm watching as it slowly drops.
I go to jump the truck from my Marauder w/a 250A alt and see a big spark when I hook up the cable to the Marauder battery so I look back at the truck side and it is hooked up backwards on the truck side. I yank the cables off, connect them correctly and jump start my truck. Took it to the store and had the battery tested and it was bad and wouldn't hold a charge.
Now I have a new alternator and a new battery but I'm only getting 12V out from the Alt (Alt tests good, took it to a store other than where I bought it from). I pull off the negative terminal and hook up a test light and i lights up when I hook the probe up between the negative terminals and negative cable. I start pulling fuses and first one that affects it is the IP fuse (50a) but I still have a bright light on the test lamp. I disconnect the PCM and the light shuts off completely.
I measured current with the PCM connected and I'm getting nearly 2.5 amps draw so I know it's toasted. I move to the interior to find the other shorts in the IP fuse panel. The 3 Fuses I found shorts on are Fuse 25 (generic electronic module(GEM), instrument cluster), Fuse 29 (radio), and fuse 35 (RABS test connector). With the test light connected all 3 off these circuits will show a short but I haven't measured current yet but my test light is very bright. I plan on swapping the radio out with an aftermarket unit I have to fix that issue, but I have questions in regards to the GEM unit and the RABs test connector.
I know the GEM is bad because C7 on the board is fried and this is the circuit that connects to Fuse 25 and splits off to pin 7 on connection C3 of the gauge cluster and Pin 11 of the T-224 connector. With just the gauge cluster connected there is no short but with just the T-224 connector plugged into the GEM it shows a short again.
For the GEM unit I'm wondering what years would be interchangeable as I have found several different part numbers but I'm not sure which ones if any would be interchangeable for different model years so I can hit the junk yard. Or if anyone could tell me the size of the capacitor on C7 I could just replace the faulty component. There's no way I can measure it or identify a part number as it is completely blackened and unfortunately I can't find a schematic of the module itself. The P/N on the module is F87B-14B205-DD.
For the RABs test port I haven't dug into much or even looked at the section of the schematic. I'm half hoping I could just disconnect it for now and hopefully didn't fry the unit or if anyone could give me a heads up on any issues they have had with the RABs unit.
Thanks for any help,
Phil
I don't post here often but have run into some issues with my 98 B4000 Auto that I need help with. I recently had some charging issue and had to replace both the Alt and battery. I also crimped and soldered new ends onto all the cables also as they ends were previously pretty corroded.
The day I replaced the alt but before I replaced the battery I drove the truck home after installing a new alt from Adv Auto. I get home and the lights are flickering and my battery gauge is reading really low. I whip out the multimeter and check the voltage and I'm watching as it slowly drops.
I go to jump the truck from my Marauder w/a 250A alt and see a big spark when I hook up the cable to the Marauder battery so I look back at the truck side and it is hooked up backwards on the truck side. I yank the cables off, connect them correctly and jump start my truck. Took it to the store and had the battery tested and it was bad and wouldn't hold a charge.
Now I have a new alternator and a new battery but I'm only getting 12V out from the Alt (Alt tests good, took it to a store other than where I bought it from). I pull off the negative terminal and hook up a test light and i lights up when I hook the probe up between the negative terminals and negative cable. I start pulling fuses and first one that affects it is the IP fuse (50a) but I still have a bright light on the test lamp. I disconnect the PCM and the light shuts off completely.
I measured current with the PCM connected and I'm getting nearly 2.5 amps draw so I know it's toasted. I move to the interior to find the other shorts in the IP fuse panel. The 3 Fuses I found shorts on are Fuse 25 (generic electronic module(GEM), instrument cluster), Fuse 29 (radio), and fuse 35 (RABS test connector). With the test light connected all 3 off these circuits will show a short but I haven't measured current yet but my test light is very bright. I plan on swapping the radio out with an aftermarket unit I have to fix that issue, but I have questions in regards to the GEM unit and the RABs test connector.
I know the GEM is bad because C7 on the board is fried and this is the circuit that connects to Fuse 25 and splits off to pin 7 on connection C3 of the gauge cluster and Pin 11 of the T-224 connector. With just the gauge cluster connected there is no short but with just the T-224 connector plugged into the GEM it shows a short again.
For the GEM unit I'm wondering what years would be interchangeable as I have found several different part numbers but I'm not sure which ones if any would be interchangeable for different model years so I can hit the junk yard. Or if anyone could tell me the size of the capacitor on C7 I could just replace the faulty component. There's no way I can measure it or identify a part number as it is completely blackened and unfortunately I can't find a schematic of the module itself. The P/N on the module is F87B-14B205-DD.
For the RABs test port I haven't dug into much or even looked at the section of the schematic. I'm half hoping I could just disconnect it for now and hopefully didn't fry the unit or if anyone could give me a heads up on any issues they have had with the RABs unit.
Thanks for any help,
Phil
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