No power, whatsoever

[TitanSvt]

Hey all, looking for some help with a new issue and hoping someone has dealt with this before.

Started the car up this afternoon, let her warm up, backed out of the garage, and she died. Tried to fire her back up, but I got nothing. No power at all. No fuel pump activation, no lights on dash, no horn..... Nothing

Pushed back into the garage.

Battery voltage still read 13.5v at battery in trunk, but 1.2v (not 12, 1.2v) at the distribution block in engine bay. Pulled main power wire and isolated that, it's good. Put the power supply wire back on and removed wire from engine fuse box to isolate that, it's good. Reattched to the fuse box and tested... 1.2v. This told me then I have a huge draw at the fuse box.

Started pulling fuses and checking when voltage jumped back up.

When I pulled the Maxi Fuse #6 (Instrument Cluster/PCM) voltage jumped up to 13.5v.

Does this sound like a fried PCM? Time for MS3 Pro?


Thanks for any help. And if I'm missing necessary information about the car, I'll gladly share that info.

Sent from my SM-G998U using the svtperformance.com mobile app

 

[fordmaster302]

to me it sounds like a bad ground at the battery location

 

[Roots-type]

IIRC that #6 maxi for the pcm was what kept blowing when the noise suppressor mysteriously came unplugged from the back of my passenger head. Not sure if that correlates, but it's worth a check. There's also one on the driver's head.

 

[TitanSvt]

to me it sounds like a bad ground at the battery location

If it was a bad ground, I don't think pulling the PCM fuse would make a difference like it did. When I pulled that fuse, (maxi #6) the voltage immediately jumped from 1.2v to 13.5v at the engine fuse box. Still no power throughout the car ie: horn, dash lights, interior lights...nada...but I have power flowing through the cables as necessary.

I could be completely wrong, as I'm no electrician, so I'll check the battery ground to chassis tomorrow and check back in. Grounds at battery terminal are solid.

IIRC that #6 maxi for the pcm was what kept blowing when the noise suppressor mysteriously came unplugged from the back of my passenger head. Not sure if that correlates, but it's worth a check. There's also one on the driver's head.

I'll check when I get a chance, but the fuse does not appear to be blown. When I plug the fuse back in, it allows the PCM to draw 12v from the battery, instantly. Removing the fuse, stops that 12v draw.

 

[derklug]

If your voltage is dropping that low with the fuse connected you have a lot of resistance somewhere between the battery and the fuse box. To pull your battery down to 1.2 volts immediately would take like an 800 amp draw. Put away your voltmeter and grab a test light, and not an led light. You need something that is going to put a load on the circuit. In a pinch, a headlight makes a good load. Now start at the battery and work your way to the fuse box.

 

[TitanSvt]

If your voltage is dropping that low with the fuse connected you have a lot of resistance somewhere between the battery and the fuse box. To pull your battery down to 1.2 volts immediately would take like an 800 amp draw. Put away your voltmeter and grab a test light, and not an led light. You need something that is going to put a load on the circuit. In a pinch, a headlight makes a good load. Now start at the battery and work your way to the fuse box.

My draw would be somewhere "After" the fuse, correct? Since my voltage is good with the fuse removed and drops when I plug in the fuse. IE; connecting whatever is creating the draw.
The fuse in question is the Maxi #6 fuse (Instrument Cluster/PCM). Could it be a bad PCM or relay in the CCRM?

 

[derklug]

The draw is after the fuse, but the resistance is before the fuse. Think of a kinked hose, you have pressure at the nozzle until you open it and then there is only a trickle. with no load you are seeing 12 volts, but once a load is put on there is too much resistance in the circuit to keep up the 12 volts. A corroded connection, a loose connection, a corroded wire, any could create the resistance that is causing your voltage drop.

 

[TitanSvt]

Thanks for everyone's help on this issue!

I replaced the CCRM, and all is good, better than before!! I'm not slowly losing voltage now, started easier, and I have AC now!!

Sent from my SM-G998U using the svtperformance.com mobile app