1998 s70 reverse jump polarity troubleshooting. Bad relays Topic is solved

Derbyrunner · Post by **Derbyrunner** » 19 Aug 2016, 11:58

I took out all the bigger fuses 50 amp and 60 amp. With key turned to on position the #6 60amp fuse labeled power to fuse box and aliment. Bootier fusib is sending the power to #10 15amp ignition fuse.

Derbyrunner · Post by **Derbyrunner** » 19 Aug 2016, 13:43

BEJinFbk wrote:That's the fuse that actually feeds the ignition switch itself.
From there it branches out to several things, including accessory
overload relays 105 and 106.
One way to deal with this is take a picture of the fuse box,
pull all of the other fuses and start putting them back one at
a time with the key on. Long way around, but it's a start.

This may help:
98 S-V70 Fuse Locations and Legends.pdf

UPDATE the beast is up and going again. The short was in the 106 relay and main engine relay or at least one of the two as I changed both. Went through about 4 boxes of 15 amp fuses but that's cheaper than other big ticketed items. Thanks to everyone for input! I really appreciate it!

Post by **BEJinFbk** » 19 Aug 2016, 14:27

Those relays usually have a spike protection diode on the coil legs.
The reverse polarity probably melted it into a nice short to ground...

Glad you got it running!

Derbyrunner · Post by **Derbyrunner** » 19 Aug 2016, 15:42

The long way around proved to be a tedious job but worked out. I went through about 4 boxes of 15 amp fuses to narrow it down to main engine relay and relay #104 I think. It's running again and I'm very appreciative of all the input

Post by **scot850** » 19 Aug 2016, 17:45

Well done for being persistent and seeing it through. Good input from all the guys who helped also!

Neil.

Post by **abscate** » 20 Aug 2016, 04:22

Changed thread title for search.
Thanks for sharing outcome as this might save someone a lot of fuses next time!

m96ag · Post by **m96ag** » 20 Aug 2016, 04:57

Derbyrunner wrote:The long way around proved to be a tedious job but worked out. I went through about 4 boxes of 15 amp fuses to narrow it down to main engine relay and relay #104 I think. It's running again and I'm very appreciative of all the input

Tip for anyone reading this. If you're doing this kind of troubleshooting go and buy one of these circuit breakers and put it in place for testing to save a pile of fuses. https://www.amazon.com/Bussmann-BP-UCB- ... reaker+atc

Post by **erikv11** » 20 Aug 2016, 09:37

Somehow I missed this thread. First step (after replacing any blown fuses) is always to replace the three J relays, they are cheap and one or more of them will always be blown.

jonl · Post by **jonl** » 30 Aug 2016, 08:38

Hi Derbyrunner,

I've a 2000 V70XC and did something similar to my car this morning. How did you know that your 106 and/or main engine relays were your problem?

Post by **cn90** » 30 Aug 2016, 09:16

Jump the relay, if car runs, relay is bad.
Or get a few spare relays from junk yard for testing, make sure you label them which is which before swapping!