CherockeeXJ

I installed an aftermarket radio. Could it be draining the battery somehow?

Bustedback

Yes.

Turbo X_J

+1

CherockeeXJ

I pulled it out for the night to see if the battery drains tonight. I took a volt meter to my battery - engine off 12v, engine idling 13.4v - so I know the alternator is charging.

I'm redoing the wiring harness. I kinda just hooked up color to color. I'm going to go back and make sure that it was all right. Also there was a clip that connected to the back of the stock headunit that was a black wire. Was assuming it was the ground. The wiring harness for the Jeep didn't have a ground so I snipped off the clip and just spliced the wiring harness for my stereo's ground wire to it.

sthon

Sounds about right. IIRC the ground was just screwed into the factory stereo, at least on my 92 it was.

CherockeeXJ

Well I'm going to go back and check the wiring between the two harnesses. I don't understand why (or even if) it's killing the battery. Guess we shall see in the morning.

jake92

Best thing to do is take a voltmeter and do a parasitic draw test.

CherockeeXJ

I have a volt meter! Now how do I do a parasitic draw test?

jake92

He explains it well and the video is a good reference while you're doing the test.

dnuccio

the thick black wire that plugs into the back of the stock radio is the antenna. the ground strap bolts to the housing with a 10mm bolt

CherockeeXJ

Wow, I'll have to watch this guys videos more often. That was stupid simple to understand. If the battery is dead in the morning I'll for sure be doing this as I'm about to go to bed. Then when I get my radio back in I'll do it to make sure it isn't causing a parasitic draw.

On my 97 Grand Cherokee Limited it was a small black wire that ran into a sort of binder clip style thing and was clipped to the back of the radio. Not the thick black one.

CherockeeXJ

The battery was dead this morning. Let the parasitic draw test begin!

UPDATE: The A/C Clutch is shorting out and drawing power 24/7. Pulled the relay until I can hunt down the short.

dave1123

On some radios, there is a small black wire on the back of the unit that is for a power antenna. If that is grounded, that could be your drain.

JJCIII

Do you mean blue wire with a white stripe? I've never seen a head unit that used the black wire for power antenna. Unless thats just stock ones

CherockeeXJ

The thicker black wire (3/4 in diameter would be my guess) that has the metal plug.

I did a parasitic drain test though and it was the A/C Clutch.