1999 V70 Husband jumped battery with wrong terminals

VolvoinPhilly · Post by **VolvoinPhilly** » 12 Sep 2014, 14:26

While I saw the forum on the 1995 Volvo 850 I wanted to be sure I should get new Power relays. I did check all of the fuses and so far they all look good. Which relays should I replace? He tried to jump it again this morning and said the car was smoking and there was a rattling/buzzing sound.

Post by **Ozark Lee** » 12 Sep 2014, 14:56

Welcome to MVS.

I'm a little confused about the references to the '95 850 but I will just assume that it references another thread. The 1999 and the 1995 are the same platform cars but electrically they are very different. Electrical stuff that applies to the 850 generally won't be the same with a 1999 V70.

Can you tell what is buzzing and what is smoking? Reversing the polarity can damage a bunch of things and there isn't any set order to what devices are most susceptible to damage. The stuff that smokes and buzzes needs to be identified first. From there, you will likely have several other things that have blown a fuse but they can be dealt with individually. Many of the electronic systems on the car have reverse polarity "protection" in the form of a sacrificial diode. The diode shorts out (and typically smokes) to try to save the rest of the circuit. The diodes on the individual circuit boards can be replaced fairly easily but it takes some soldering skill and a certain amount of cleverness to get the modules or devices apart. At least identifying them is pretty easy, it is the device on the circuit board that is burned. The only hard thing is to figure out which direction to orient the new diode when it gets soldered in.

If you can give us more information we can likely help you sort it out. Even if you make a YouTube video and post a link that can help.

...Lee

Post by **oragex** » 12 Sep 2014, 15:43

Have a look at the alternator and it's regulator.

VolvoinPhilly · Post by **VolvoinPhilly** » 12 Sep 2014, 18:32

When my not so swift husband came home from work I jump started the car myself. Initially I saw nothing then after about 2-3 minutes I saw light smoke coming from the alternator. I replaced it 2 years ago so I am really annoyed now. I am guessing the rattling is because my husband is not used to hearing a car with a manual transmission. It sounds different than an automatic which usually sounds quieter to me.

Post by **abscate** » 12 Sep 2014, 18:41

It sounds like the diodes in the alternator might have fried. This would also explain why you have to Jump it, the alternator is no longer charging the battery.

New or rebuilt alternator is first on the list.

Be extra attentive to how your car is running for the next week. I used a school bus start pack on my 1999 one winter and one week later one of the coil packs died, stranding me in -20F weather.

This is not a good thing to do to a highly electronic car. Maybe put some red tape on the positive terminal to make it harder to mix up next time.

VolvoinPhilly · Post by **VolvoinPhilly** » 12 Sep 2014, 19:38

I take care of the cars in the family because my husband does things like that all of the time. I went out and put an X near the positive terminal with nail polish. I am hoping nothing else is messed up. Luckily the mechanic is 1 mile away and only charges me about $90 for an alternator.

Post by **erikv11** » 12 Sep 2014, 22:27

Regarding the question in your first post: Yes, you should expect you will need to replace all of the J relays. I don't know how many there are, maybe 2 or 3 or 4. Some of them may be OK but they are pretty cheap, especially at a junkyard.

Those J relays are primary safeguards in the electrical system against crossed jumper cables. So expect that they need to be replaced.