Radio goes off when putting it into Reverse

[70sixpkrt]

I changed my transmission gear oil today and noticed that when I put it into Reverse my radio goes off and then on. It did blow the fuse once. It's a 4 speed. I was using Passon Perf gear oil and switched to 85W90 gear oil. I did add the trunk light harness that is behind the drivers side kick panel last month. I don't remember if it did this before adding the trunk light harness. The stereo is an aftermarket one which I put in about 20 years ago. Could it be a bad reverse switch at the tranny?

[Kern Dog]

If the ground for the radio is wired into the backup light switch....
If the positive for the radio is tapped into the power for the backup light switch...
Heck, I don't know. I fumble my way through a LOT of this shit and sometimes I win, sometimes I ask for help.

[70 sublime]

I think if your radio is wired up like factory originally the power wire for the radio comes from the fuse box and at the radio plug the power splits with another lead that is the power supply for the back up light circuit
Maybe try unplugging the back up lights at the back of the car and see if weird radio stuff still happens when in reverse
Could be a bare wire between here and there causing a short

[70sixpkrt]

So I unplugged the plug to the reverse switch on the tranny. Car on accessory put it into reverse the radio stays on. No reverse light on the dash since it is unplugged.  Hooked up a jumper wire from one female to the other female lead on the plug. Car on accessory the reverse light on the dash is on. Put it into reverse and the radio stayed on. To me it sounds like a bad back up light switch.

[nitrousn]

The back up light switch has nothing to do with the radio. Unless someone has hacked the wiring or you have a wire that is melted into another. The radio is on a separate circuit.

[70 sublime]

The back up light switch has nothing to do with the radio. Unless someone has hacked the wiring or you have a wire that is melted into another. The radio is on a separate circuit.

Look up a factory wiring diagram
The power pick up for the back up lights comes from the plug that plugs into the radio

[70 sublime]

So I unplugged the plug to the reverse switch on the tranny. Car on accessory put it into reverse the radio stays on. No reverse light on the dash since it is unplugged.  Hooked up a jumper wire from one female to the other female lead on the plug. Car on accessory the reverse light on the dash is on. Put it into reverse and the radio stayed on. To me it sounds like a bad back up light switch.

Sounds like your switch is the problem if the radio stays happy and the switch is by passed

[nitrousn]

The back up light switch has nothing to do with the radio. Unless someone has hacked the wiring or you have a wire that is melted into another. The radio is on a separate circuit.

Look up a factory wiring diagram
The power pick up for the back up lights comes from the plug that plugs into the radio

That may be correct however the power to the radio is never controlled through the back up switch. The fuse is key powered and then directs its path to the radio and what ever else is in the circuit. You can unplug the back up switch or cut the wires at the back up switch and the radio will continue to play. The car is most likely mis wired.

[70sixpkrt]

Why would it do this directly after I changed the tranny fluid? No problems before this.

[nitrousn]

There is no relation. I guarantee it is not a backup light switch causing your radio problems. You have wiring problems somewhere. If its an aftermarket radio its most likely wired wrong. You changed something or you have wire problems.

[70sixpkrt]

What if the back up switch is shorting the radio out whenever I put it in reverse causing the radio to go off and then on? The radio and back up switch are controlled by the same fuse.

[Kern Dog]

Was it the Ficklesnort relay?

[70sixpkrt]

So I unplugged the plug to the reverse switch on the tranny. Car on accessory put it into reverse the radio stays on. No reverse light on the dash since it is unplugged.  Hooked up a jumper wire from one female to the other female lead on the plug. Car on accessory the reverse light on the dash is on. Put it into reverse and the radio stayed on. To me it sounds like a bad back up light switch.

Sounds like your switch is the problem if the radio stays happy and the switch is by passed

I unplugged the plug and hooked up a test light. I put it in reverse. Grounded the test light and then touched the each terminal on the switch. No light from either side. Did the same with the plug. Light came on and radio stayed on. Bad back up switch?

[nitrousn]

You need to put 12 volts to one back up switch terminal. I assume this is a 4 speed. Then test the other switch terminal it should go on and off when you shift to reverse. Testing it your way the light will never come on. Again you have wiring issues.

[70sixpkrt]

I don't understand why I would have a wiring issue. All I did was replaced the tranny fluid. Nothing else. The tranny fluid that I used was an old open gallon.

[Kern Dog]

You are not getting it. I've seen this response from you in other forums where you have posted this question.
Sometimes an issue pops up at the same time that you did something UNrelated. This is PURE coincidence. If you add coolant and later run out of gas, walking to the gas station had absolutely nothing to do with adding anti-freeze, they just happened at about the same time.

[70sixpkrt]

Kern Dog I have posted in other forums to get feed back and answers. If you don't have an answer, don't reply. I have seen your responses on other forums.

[nitrousn]

He gave you an answer and a correct one. Obviously your skin is thin and I wont make it any thicker. Here is the way it is. No one can answer your question correctly. You refuse to accept common sense answers. You refuse to accept that the radio is not controlled by the back up light switch. You want someone to go along with your thinking and get pissy when they don't. Fact is your car is screwed up most likely mis-wired. You obviously are clueless when it comes to wiring. You need to get a diagram and get someone to help you before you create a smoke bomb. Sorry but that's the way it is. Once I sneezed and crapped my pants. I must need a new nose right.......

[charger Downunder]

Under the steering column there is two flat wire plugs with multiple wires have a look at the plastic plugs on the side for a brown burn mark if so bad connection in the plug.

[70sixpkrt]

So I got a new back up switch yesterday. Plugged the plug to the new switch and pressed the ball bearing. The reverse light went on and the radio stayed on. I touched the switch to the trans for a ground and pressed the ball bearing. Reverse light went on and the radio stayed on. Looks like it was the switch. I'm glad I didn't take my wiring apart and I am not clueless. Common sense.

[70 sublime]

 

[Kern Dog]

It is GREAT when a problem is fixed this easily!

[nitrousn]

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