12 volt Aux battery dying; solved.

Well, since I had to fix the traction battery this week I figured "in for a dime, in for a dollar." The car I bought was a salvage vehicle that had been rebuilt. The re-builder did a very nice job putting everything back together.. I thought.

On pesky problem was found after I'd had the car for about 4 months. I let it sit for three days. When I went to start it nothing happened. Yep, the 12 vdc Aux battery died. It tried charging it and it wouldn't charge. I bought a new aftermarket battery at WalMart and installed it. Merrily being led down the garden path I figured I'd not see that pesky problem again.

I was wrong. It continued. About the time I was going to tackle it, I moved... and that took the next 4 months and the Prius sat since late February when the HV Traction battery error cropped up.

This week I figured since all the carpets and shrouds were out of the trunk for the battery repair I'd look at the luggage courtesy light, it was the most obvious cause of an error. Sure enough the lamp would not shut off even though it seemed to operate correctly. It pulls up ground and turns on the light.

I looked at the switch assembly a little closer and found that the switch was bent. When the switch plunger was up it turned on the light. That was normal. However, when the switch plunger was down, the plunger hit the body of the bent switch assembly, thus pulling up ground and turning on the lamp. In short it never turned off except for the brief distance of the plunger travel.

Bending the switch tab down freed the plunger and brought it away from ground when the trunk was lowered. I'm pleased it was that easy. But I know that it's also a problem that can be often overlooked.

Good Hunting.

 

The luggage courtesy light is mounted in the trunk, on the body of the car. It's often called "The Trunk Light".... and lets you see the contents of the trunk at night.

It comes on when you open the trunk and is turned off when you close the trunk. Here's a picture of it looking up from about where the trunk latch is on the body of the car.