Please help! stuck in parking lot. 12v at battery 5v everywhere else

[DSMTurbo2]

Hello, I am having an odd issue. Seems like a good short or bad ground.

I unlock my car via alarm. all functions properly.
I step in, close door, go to turn key in ignition and all power shuts off (radio, seat belts, dash lights.... everything)
I turn the key back to off and the auto seat belt motor groans and chugs but doesnt move anything and nothing turns on. everything acts as though the battery is extremely low or dead completly.

I walk to my local super store and grab a cheapy volt meter. Going from positive post to good ground on chassis I get 12v. I move off the post and onto the battery cable and instantly get 5v, which is what I get anywhere else I probe for electricity.

any thoughts?... any way to get this home? I think I might go grab a new ground cable, even though this one is not that old??? I dont know!!!

Please help!!

Thanks Erik

 

[coryf1233]

i would try to find the point where the voltage dips to 5v. If you could pinpoint the exact spot at which the 12v is lost, then perhpas that component has an issue

 

[DSMTurbo2]

i would try to find the point where the voltage dips to 5v. If you could pinpoint the exact spot at which the 12v is lost, then perhpas that component has an issue

Yeah that is what I am saying though. It drops to 5v right after the the battery post. I can check voltage on the post and it is 12v, and then right on the post connector for the supply wire it drops to 5v. The terminals are spotless. oh and this is with no load on the car other than maybe a door open.

 

[i_nick_2005_i]

If your connections are all secure, then I'm not sure. It seems your ground is fine, seeings how when the positive is on the battery and negative is on chassis it's showing 12V. That would lead me to believing your positive cable is failing to make the connection. I would try a different battery, from a friend or relative and make sure it's a wiring issue and not a battery.

 

[i_nick_2005_i]

It HAS to be your post connector.......A constant good length of metal will not lose any voltage from point A to point B given that it is a solid connection......Even if it a was a extremely tiny fray of a wire it would still have 12v down the line.....You've got something majorly shorted out or wierd going on there. Sorry I can't help out.






Edit: As 95redturboawd stated, I would go get a wire brush and polish everything. That should do the trick.

 

[95redturboawd]

Yeah this happened to me. The clamps that are on the posts of the battery were painted red and black to signify which was which and the paint was causing a bad connection between the posts and the clamps. Scraped the paint off, fixed the problem. Also make sure the clamps are tight on the posts.

 

[wondersb]

If you have a battery pack try to boost it from the starter bolt and a good ground. by pass your cables all together. That will get you home. Then start cleaning all your cable ends, start doing the cheap stuff first

 

[bomper04]

if you had another person with you i would recommend doing a voltage drop on your terminals to post. seems like there's a bit of corrosion..