Defroster switch shorted, now overdrive light stays on-help!

kushaballz · Post by **kushaballz** » 17 Jan 2005, 15:30

Hey all,

I was replacing a light bulb for the seat heater switch and the rear window defroster and accidently shorted out the two light bulb terminals on the back of the defroster switch while testing the wires for voltage, and now, the overdrive light turned on and won't turn off. I'm not sure if the car is actually stuck in overdrive because i'm getting the car ready for safety and emissions inspections (a required inspection in VA to have your car on the road), and can't drive it yet because of that. By the way, I also tried switching it via the overdrive switch. Any Suggestions?

Car-
1985 Volvo 240 DL
Station Wagon
Auto. Transmission
B230F Engine
Fuel Injected

Thanks in advance

LaRy · Post by **LaRy** » 18 Jan 2005, 12:23

Sorry, but most probably you are stocked in overdrive disengaged. That is actually what the lamp indicates.
The lamp is connected in paralell with the voltage feeding the solenoid in the transmission. If you have some electrical experience you can test the following things. Disconnect the OD relay and look at the terminal numbers. Then you can do some checking by messauring the resistance and voltage at the socket.
At pin 15 you should have (with ignition on) +12volt. The same 12 volt will be found at pin 86 just while closing the OD button. Pin 31 is connected straight to ground. 87 and 87a are connected together in the relay. Pin 87a is going to the indicator lamp, should be some ohm to ground from the lamp. Pin 87 is connected to the solenoid coil, it should be 13 ohm to ground.
I do not see any reason why you need this relay if you don't use this OD disengage function. It should be working good without the relay.

kushaballz · Post by **kushaballz** » 19 Jan 2005, 12:44

I found out that it had a blown fuse in the fuse panel. I was unable to notice that it was blown out because it was dark when I checked

LaRy · Post by **LaRy** » 19 Jan 2005, 13:21

It is always nice to get some feedback. Very often it is just a simple fault, but it will help others. Interesting that a blown fuse can make the OD lamp to light, but everything is possible in cars.
I think we should be better in this forum to give a reply how the fault was solved, like kushaballz made here. Thanks!

jacqueb · Post by **jacqueb** » 12 Jun 2005, 18:24

What does the overdrive light look like and where is it located? ! I recently purchased a 1999 Volvo S70 with 103K miles. BUT there is no owner's manual. Today I noticed a yellow arrow light came on at the right side of the panel. When I shut the car off, it did not come back on. Does anyone know what that light indicates? Thank you.