I couldn't find a forum listing 1998 f250 5.4 gas so thought I would try here. I am having electrical issues that started with a parasitic draw, found 6mos old battery dead one morning - jumped with another car idled for a while drove around the block and parked it. Next morning dead again, jumped it, idle for an hour drove it about 10 miles and dash warning lights started blinking. I had noticed that the ignition key didn't seem to have "stops" between lock-off-run so picked up new ignition switch and drove 10 miles home. Parked and left truck at idle, got out to fetch multimeter and the starter motor attempted to engage. Shut it off and replaced ignition switch restarted same issue with lights and starter. scanned for codes and got B1352 ign key in circuit B1867 power supply (ECU) circuit short to ground. Removed battery from truck put on charger and disconnected PCM to check wires in harness (outer wrap was missing indicating someone had been in there before). Didn't find anything there that indicated a major short, so plugged back in to pcm and used jumper cables to supply power, intending to look for short via voltage drop on fuses. Before I could touch the leads to fuses the horn sounded on steady, headlights and windshield washers came on. Cut off power, pulled horn fuse and re powered lights and wipers came on switches had no effect. Would a bad PCM be likely?

 

Thanks for the reply. SpringerPop had suggested checking the GEM, I am assuming that is the BCM you are referring to. Is that right? After removing the fuse panel to get at the GEM I noticed rust and green corrosion at the bottom of it and I will be replacing it. The GEM does not appear to have had any water incursion so I am hoping that it might still work. Ford parts.com shows my vin as a F250 super duty which it is not, chatted with a rep who said it called for part# EL3Z-14b205-CRM which is no longer available and suggested two parts suppliers neither of which had it. The GEM on the vehicle is # F75B-14B205-ND. Still looking for that part or a source for rebuild/recondition.

 

Update, I installed fuse panel with my old GEM and the accessory hi jinks are gone for now. Still have the parasitic battery drain issue so going back to looking for short to ground. May have to replace GEM after all.

 

Update 2, Could not find any obvious shorts so started it up and... the battery light stayed on. No output from alternator, took it off and had it checked it was bad. installed it but still no charge. found bad 175amp mega fuse was bad. Ford dealer doesn't stock them would have to buy 5 and wait 1-2 weeks to get them. Parts stores say Littelfuse 175 does not fit my vehicle, couldn't tell me why. Anyone have thoughts on using it?