94 850 Keep losing all electricity

skloon · Post by **skloon** » 22 Sep 2016, 12:32

I will periodically lose all electrical power- it seems to happen when I slow down- I have cleaned and re-tightened the battery cables- the alternator puts out power and the battery holds a charge- is there a relay that swiches all the power ?

Post by **JDS60R** » 22 Sep 2016, 12:40

Wires from battery to main fuse box have always had a corrosion issue. Many posts here on how to replace or improve.

I am assuming you mean all electrical power not just engine shutting down.

Post by **cn90** » 22 Sep 2016, 12:44

You either have to drive faster (j/k) or search forum for B-Cable issues.

Post by **kcodyjr** » 22 Sep 2016, 13:02

Don't forget the ground strap to the block, as well as the battery ground cable. Either of those could interfere with the alternator getting power out of the engine and into the rest of the car.

Post by **erikv11** » 22 Sep 2016, 14:38

Next time it happens, jiggle the key ever so slightly. Or, try to replicate the problem that way. This is to test the electrical portion of the ignition switch, very common faliure.

skloon · Post by **skloon** » 23 Sep 2016, 12:09

The ignition switch is only 3 months old- the old one was sticky and I had a spare- does the 850 have the B cable issue, I thought that was only v/s70s ?

Post by **erikv11** » 23 Sep 2016, 17:38

B cable issues are uncommon on the 850, you are correct. However corrosion at the main starter cable end, where the wire goes into the lug, is a common problem. That suggestion for grounds is looking good too.

Post by **misha** » 23 Sep 2016, 17:56

Positive battery cable(b+) failures ARE common on these cars...but the part from battery to starter.The other part is going from starter to alternator and is not a problem...if erikv11 was thinking about that one.
I also had a bad one few years ago.

You maybe have a problem with both...b+ and negative cable major voltage drop.

Post by **erikv11** » 23 Sep 2016, 20:32

Yeah, I have replaced the battery-to-starter cables already on three of my cars including two 850s; those are definitely an issue, especially at the battery end. Feel the cable end after using the car, is it getting hot (it shouldn't)?

Here's what I mean: the cable from the battery to the fuse box is a big problem on 98-00 cars, including at the end in the fuse box. On the other hand, the fuse box end of the cable is essentially zero problem at all on the 850s. Check the cable ends near the battery first.

Post by **abscate** » 24 Sep 2016, 01:12

It's a 22 year old car being used 3x past its typical life. Everything is suspect. It's a lot faster to diagnose by method than by symptom/lookup table approach.

Here it's battery, cables, grounds.

Do you lose all power to everything?
How old is the battery ?