Weird electrical problem when trying to start... won't turn over

[nick26]

Hey guys,
Like a week ago I was driving and suddenly the car just cut out on me and all power was lost. So I pull over, take the key out, check under the hood, everything looked fine. I get back in and put the key in and it starts up just like normal except my clock and stereo had been reset like the battery was disconnected. I drove it a few more times after that and it was totally fine. Then I goto start it the other morning and I put the key in, turn it to start and the power totally dims and the starter doesn't turn at all. If I turn the key to the accessory position the stereo and interior lights work fine. But when its in the on position I can only very faintly see the instrument panel lights and the interior light is on but very dim.

This is the weird part now, if I leave the car for a few hours and come back to it, put the key in, turn it to the on position without trying to start it, all the power works fine. As soon as I try to start it, the on position is stuck in the very low power mode.

I tried jumping it and that didn't matter, I checked all the fuses and starter relays under the and they seem fine. Something else thats weird is I noticed if I leave the car in the on position I get a bunch of sporadic relay clicks coming from the coolant computer next to the radiator fluid reservoir. I took it out and took the cover off but everything seems fine inside of it. I figure its clicking because their isn't enough juice to keep the relays closed continuously. I wouldn't think this little box would cause this kind of problem anyway.

Sorry for the long read, just wanted to give as much info as I could.

So anyone have any ideas what to start trying to replace? Could a bad battery wire cause this? The car has 125K on it and this is the first problem like this that I know of. Also FYI the check engine light was not on before this but the airbag light was.

Thanks

 

[Stanger007]

Sounds like a bad ground to me. I had a similar problem on my '90 Mustang - the cables looked fine from the outside but one of them was corroded on the inside. Took the cables to the parts store to match them up with the proper length and the problem was fixed.

Trace the negative cable coming from the negative post and check the connections. There's also a ground wire that goes from just above the oil filter to the frame rails (about 1.5ft of braided wire).

Wes

 

[BlueOvalStangGT]

+1 on the bad ground...my car did the same thing. I replaced my battery clamps and checked my grounds.

 

[HISSIN50]

It's possibly a bad battery or battery connection as well. Charge yours and have the battery load tested (now that it's getting hot, batteries are taking a dump often).

For quick ground testing: grab a jumper cable and attach it to the top of your engine (nice shiny metal on the intake, etc) and run the other end to a clean spot on the frame. See if it helps. All of us should clean our OEM engine grounds and add another one. I chose to do so on the passenger side (as as to mimic the OEM one on the driver side).

Good luck.