Backup lights switch

Believe its on the tranny.

Whitelightning

Is it the half moon shaped thing on the drivers side of the tranny with the four wires comming out of it?

Thanks! Gene

Yes.

Especially if that is where the linkage goes into the trans. The switch is normally called a Neutral Safety Switch, it's job is primarily to limit starting the engine in P or N. There may or may not be other jobs it does, but you don't seem to be conserned with those jobs.

Yes it where the linkage goes into the trans. I removed the switch yesterday, cleaned it up, turned on the ignition and cycled the switch several times using my finger while my friend stood at the back watching, no lights came on. I then unplugged the switch from the harness and tried jumping the power with a small wire, still no backup lights. As I was doing this one of the connections I made seemed to make a device run that is located at the front of the motorhome, sounded like a air pump? At this point I figured I was working on the wrong switch and put it back together. Now that I read your reply Jeff and I gather I was working on the right switch, but I'm puzzled about the lights not coming on when I used the jump wire?

Thanks for your feedback!

Gene

Are you sure the bulbs are good? Have you checked the wires going to it? Motorhomes sit a lot and furry creatures seem to love chewing on wires. Do they have a good ground, more then likely they all share a common ground.

Whitelightning

First thing I checked when we (Dad) and I discovered there was a problem with the BU lights. Bulb condition all excellent, confirmed with meter, then did a continuity with the multi meter and it beeped so I assumed I had a ground. I think I will run a new ground wire now that you bring it up...just cant trust the meter. Hope I get lucky, I'll let you know how I make out tomorrow. Thanks again for your help!

Ok, back to back-up light repair. My son broke his arm and I was busy with work so I had to delay diagnosing the problem for a few days. Today I ran a positive (hot) wire from the battery to one of the power wires on the back-up lights. I had a dead short (wires started to melt). I quickly identified the short in one of the aftermarket BU lights and repaired the problem. Next I reran the hot wire to the power wire on the light and all 4 of the back-up lights came on. Ground must be good, fuse is good, but still no BU lights when I turn on the key and shift into reverse. Could there be more than one fuse? Or am I back to replacing the switch on the tranny?

Thanks! Gene

back to replacing the switch. and a suggestion. Let me guess that the "aftermarket" add on back up lights are rather large as in driving lights or fog lights? pulling a lot more amperage than the stock ones that use 1156 bulbs. Use a relay, plain jane generic one for fog lights, feed 12 volts with at least 12 gauge wire to the relay, then from the relay to the add ons. the trigger for the relay will be the feed from the reverse switch and of course the 4rth connection to the relay is a ground. and don't forget a fuse in the 12 volt feed to the relay. The switch was not designed to carry that much of an amperage load, and the dead short more than likely cooked the reverse light contacts, lucky it didn't toast the neutral safety side as well. Eventually the extra load would have done the switch in anyways, the short just sped things along.

Whitelightning

After reading your excellent advice today I got out the owners manual for the Eurocoach and now can confirm the "aftermarket" BU lights are a stock item on the motor home. One would think that a professionally built unit would have come with a relay on the extra set of lights? I will first go shopping for a tranny switch tomorrow and if that doesn't fix the problem then I'm going to continue to look for the relay. I did find a relay that looked like it was connected to the tranny switch but when I jumped the power it kicked on the fuel pump. I think that was the noise I heard when I first started this project. Thanks for your help Whitelightning; I'll keep you informed of my progress.

Gene

I'm with whitelightening on this one. You need to make sure the lamps are good, the ground to the lamps is good, and the power gets to the lamps. I'd pull a lamp or two, and use a volt meter to make sure there is voltage on the pin inside the socket. If there is, then the switch in/on the trans and the wires are all good, and the ground or the bulbs are suspect. It is also possible that the Reverse Switch on the trans is not part of the Neutral Safety Switch, and is an entirely separate switch. (A manual trans has a switch that is struck by the gear-fork inside the trans. An automatic would reasonably use the neutral safety switch, but it could use a different switch.)

I have a BMW that has voltage to the back up lights, but the Reverse Switch (manual transmission) is so dirty that the resistance on the circuit is very high, and the lamps will not light because the additional load cause the voltage to drop. (I pulled the bulbs and measured voltage, then put the bulbs back in and the voltage went away.) The moral of that digression is that you may feel voltage at the bulb(s), but the lamps don't come on. This would be an indicator of a dirty or worn out Reverse Switch.

Well to make a long story short I just hotwired in a new power wire and manual switch. I tried to get a used safety/neutral switch for the trans but apparently they are a rare item for C-6. I'm good to go for now. Thank you for all the help!

Gene