99 V70 Reversed Polarity jump starting: dead

crispymoon · Post by **crispymoon** » 06 Feb 2014, 16:47

My son left the car keys in last night, trying to reset the radio code and this morning the car turned over but wouldn't start.
After work, with my VW Passat I tried to jump start it (something I've done lots of times without incident with other cars). I should confess here that I was tired and frustrated and cold and angry because i noticed that he took out a fog light on a snowbank too.
I left the cables connected, crackling at first then stopped until my son noticed they were backward!
The passat has a sort of velvety box around teh battery and i connected the positive to the pole with the red wire going to it!

The cables melted a bit.

The volvo won't even turn over. Nothing. dead as a doornail. The VW SEEMS ok.

I'm wondering if I need it towed to a garage or if I should check things here first,maybe new battery? Did I perhaps do major damage?

Post by **erikv11** » 06 Feb 2014, 17:45

You'll need a voltmeter, else send it to the shop.

(1) Check the positive battery cable for continuity to the alternator. Also check the B+ cable from the battery to the fuse box.

(2) The main relays are almost certainly cooked, test them or just replace them. I don;t know where they are on a 99, look at your owner's manual. Here is some info about where they are on a 98 or on an 850 (https://www.matthewsvolvosite.com/forums ... =1&t=61628).

(3) Even if you get it going, there is a good chance the voltage regulator on the alternator is also cooked.

(4) Is there any voltage at all on the battery? I would try trickle charging it and see if it charges and holds charge but it, too, may be dead.

I would start with those, go from there.

Post by **QuirkySwede** » 07 Feb 2014, 00:08

Have you tried just using the VW battery with the Volvo's out of the loop (pull one terminal and jump to connector) to see what does or doesn't work with power, then checked respective fuses or fuseable links?

Post by **mikealder** » 07 Feb 2014, 07:14

Did you try to start the Volvo with the other battery cross connected? if not concentrate your searching to the positive and negative cables from the battery, if you have been lucky one of those might have blown before too much damage has been done to the car.

I know the pictures depict the right hand drive version but the US spec car is the same with the boxes on the other side of the car, both LH & RH use the same numbers for the same functions. For a 99/00 model the relays are as follows:

Relays in the relay/ fusebox in the engine compartment

1 Main relay fuel injection system (2/32)
2 Glow plug relay (diesels) (2/14) (MSA)
3 Electronic thottle module (ETM) relay (2/134)(Denso/ ME7) / Relay starter motor (2/35)
4 Relay A/C (2/22)

Relays in the central electrical unit

101 - 102 Control Module, Cruse control (4/3) (FENIX)
103 Relay fuel pump (FP) (2/23) (Not MSA)
104 - 108 Headlamp relay with bulb failure warning sensor (2/1)
105 Overload relay X supply (2/30)
106 Overload relay 15I supply (2/6)
201 Fog lamp relay (2/2)
202 Relay alarm horn (2/77)
203 Intermittent wiper relay (2/4)
204 Intermittent relay tailgate wiper (2/16) (S70/V70) or Audible signal softop (7/117) (CONV)
205 Relay rear hatch opening (2/67) (CONV)
206 Relay window lift mechanisms left-hand side (2/99) (CONV)
208 Relay heated rear windshield/ door mirrors (2/44)
210 Relay window lift mechanism right-hand side (2/100) (CONV)
212 Relay seat belt reminder/ key warning (2/5)
214 Automatic fuses 11C41-42 (CONV)

Other relays

Engine cooling fan relay (2/11)

Bulb failure warning sensor, rear (7/1)

Relay heated rear seat (S70/V70) (2/43)

Relay heating plugs coolant (MSA) (2/74)

Post by **cn90** » 07 Feb 2014, 07:44

Most of the time, just blown fuses etc.
This happens quite often in the BMW E39 forum lol!

I posted a whole bunch of photos on locations of the fuses in forum.

Post by **erikv11** » 07 Feb 2014, 08:14

You may need to check fuses but most of the time with the 850/x70 cars, it is blown relays. I'd start there.

You especially may want to look at relays 105 and 106, see the very helpful post from mikealder.

Post by **cn90** » 07 Feb 2014, 10:16

1+,

In real life, this is what the fuse box looks like...

Post by **erikv11** » 07 Feb 2014, 10:55

Great pic.

It's those J relays, go straight to those and check them out. You may want to check many things but those J relays are designed to fry out and spare other electrical parts.

Post by **abscate** » 07 Feb 2014, 17:32

On the 1999 on, it's likely the ignition coils are blown , too,

Post by **cn90** » 08 Feb 2014, 06:15

I am old-schooled and use the standard jumper cables.

However, on the same topic, people now make "SMART" cables, no matter how you connect them, they automatically detect the correct polarity for you:

https://www.amazon.com/Michelin-5100-Jum ... B002RRZX06

I wonder if this makes our society any smarter...admittedly I like this technology though (although I don't own it)...