'98 S70NA battery drain, RESOLVED fuse 15 circuit load

Post by **dosbricks** » 11 Apr 2014, 14:17

Our S70 was loaned to a niece who needed transportation. She passed away due to pancreatic cancer, and we got the car back. It had sat for quite a while in the humid Houston climate. When we went to pick up the car the battery was completely dead and had to be replaced. We elected to trailer it home because it was overdue for a timing belt change, which I just did successfully. But the car runs the battery down very quickly. When we started the car on the trailer, and a couple of times right after that, there was a pretty loud metal screech that wasn't there when we started it up in Houston to load it up. At the time I thought the starter might be corroded and cashing in it's chips.

I have just replaced the pos. battery cable because of extremely bad corrosion at the pos. terminal clamp going down into the wires. I cut the 4 smaller red wires back past their corrosion and spliced on #12 pigtails to get them back to original length and terminaled them together in pairs and attached them to the stud on the new + batt. cable. I thought maybe the corrosion had been preventing the battery from accepting a full charge.

But the new charged up battery was drawn down to 11.98 volts the next day which is not good. The car now starts normally when the battery is charged, but obviously there is a big drain. I used a multitester set to DCV to measure the drain between the neg. batt. post and the disconnected neg. batt. cable. and it read 12.89v--same as the battery voltage. Did I do this right? Shouldn't I just be seeing the normal parasitic load?

Next I pulled one fuse at a time with the multitester on DCV and none caused the drain to go away. So I removed the nut on the solenoid and tested it with the big red wire removed that goes off into a wiring harness. The result was no change. So I'm thinking maybe a bad starter??

I may be screwing this up in my methodology, so I could sure use some advice about whether I am diagnosing correctly, and if indeed the starter is at fault. BTY, the old battery cable is tied off and not in play. Thanks, and sorry for the long post.

Dos

Post by **abscate** » 11 Apr 2014, 19:06

You need to measure the amp draw, not the voltage, flowing through your positive or negative battery cable. Try a 12 Volt light first, if it glows bright you have a huge short somewhere.

If it's dim then you can test with an ammeter on the 1 Amp scale...you want to see less than 50 mA (0.050Amp) draw.

Post by **dosbricks** » 11 Apr 2014, 19:17

OK, egg on the face post here. Looks like I correctly started out using the DCA side of my meter, but opened a door and blew the fuse on the DCA part. When I got a zero read out then I thought maybe I was supposed to be using DCV. So I'll get a fuse tomorrow and start over. Thanks much, abscate.

Just in case, can anyone tell me if on an S70 there is any other fuse panel other than the one mounted on the cowl area under the hood?

Post by **rspi** » 11 Apr 2014, 19:40

Between the drivers side strut tower and the brake fluid reservoir there is a panel labeled "MAIN FUSES".

Post by **dosbricks** » 20 Apr 2014, 13:26

As I always try to eventually follow up on a request for help with the resulting fix, I got my meter squared away and quickly traced the fault to the interior lights circuit (fuse 15) then narrowed it down to the overhead switch panel--these Volvo plastic switches are not worth a flip

when they get old. With the interior lamps out of the circuit, the battery draw has gone from OL >250mA to around 26mA which amounts to about .03v of battery drain over 24 hrs.

Thanks and appreciation to all who advised and who regularly patrol this forum for those needing assistance.

joe_pinehill · Post by **joe_pinehill** » 20 Apr 2014, 14:13

does it have an aftermarket radio or original factory? If there is a battery drain , I always start with the radio for trouble shooting.

Post by **dosbricks** » 20 Apr 2014, 14:34

Radio is original Volvo, but I believe the draw is now well within the normal parasitic load. Fuse 15 circuit was the one that shot it to OL.

Post by **abscate** » 20 Apr 2014, 17:47

You nailed it, well done.

We are sorry for your lost one.

Post by **Ozark Lee** » 20 Apr 2014, 19:20

The interior lighting load can fool you since they time out. The only valid parasitic test when dealing with the interior lights is to close the doors and let them time out first. The glove box light switch has been a source of trouble on many of the 850s but I don't hear about it as often with the 70 series.

...Lee