Back-up lights on in all gears but not reverse.

I did some troubleshooting this past weekend and fixed a shorted wire between the back up lihgt plug and the back up lights themselves. I tested it out and it worked fine... Or so I thought. I tested it in reveerse and they lit up. In neutral with the car on there are not lights, and with the ignition off the lights are off regarless of where the stick is. The only thing I didn't test was with the ignition on and in other gears. Well, my wife just took it for inspection and called me with bad news. The inspector found that when the car is in first through fourth the lights are on. I don't know if he just didn't test fifth, or if the lights don't go on in fifth. Regardless, does this sound like a bad switch, or is some linkage messed up somewhere? I thought that when switches failed they just didn't pass current any more.

This is a 98 legacy obviously with the MT and AWD. It's a 2.2 if that matters.

Ideas? Experience with this?

Bill

Reply to
weelliott
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I just realized that it is possible that when I thought I was wiring into the backup light switch, I might have been wiring into a neutral switch plug. Is there a neutral switch on the manual transmission? I know autos have this for the neutral safety starting circuit. I've never known a manual transmission to have one. Perhaps it has one for cruise control? If this is the case and I've tapped into the wrong plug, it raises the question of where is the correct plug?

Thank you for any help, Bill

Reply to
weelliott

Neutral switch might be used for the ignition state (has to be in neutral to turn the key), so it makes sense there would be one.

Reply to
.._..

Actually, I think I've figured it out. I did a little searching on here and found that there is a neutral switch on the manual transmission. It is not for the start circuit though like on an auto. The car can be started in gear. It simply needs to have the clutch depressed. The neutral switch on the manual transmission is for the cruise control. If the car is in neutral it won't engage the cruise control. It also shuts off the cruise if the car is knocked out of gear without using the clutch.

When I ran new wire to the lights, I tapped into a brown plug by the throttle body on the passenger side (North American car) of the car. I think that that is the neutral switch. According to the pictures of the backup light switch on rockauto, the plug should be grey. I don't know if that is the actual picture of the exact part though. I'm going to muck around under the car when I get home and see if I can find another switch under there, and see where the plug is for it.

Anyone know where the plug for the backup light switch should be?

Thank you for the help, Bill

Reply to
weelliott

I had this happen on a Toyota, a Mazda and a Nissan.

Seems the Japanese have some kind of switch that is used for 5th gear. I wasn't able to get a lot of info on it, but it has something to do with the emissions system when the car is in 5th gear.

It sounds like the switch is stuck, although that doesn't explain why you have no lights in reverse. At any rate I would look for another connector (or, perhaps whatever feature this is it is unused in the US) and reconnect the connection you have to the proper connector so the reverse lights come on when they're supposed to!

Your local Subaru dealer may be helpful. Mine is 32 miles away, but the parts guy and the service manager happily let me pick their brains, because they know I'll be back for parts...

Reply to
Hachiroku

Well, I know I put out lots of info, and at different points certain things were wokring, then not, or vice-versa, but it started out that the backup lights weren't working, then Once I 'fixed' them, the backup lights came on in all gears, but not neutral.

I found the cause. It was my own stupidity. Not really, but perhaps carelessness. I had tapped into the neutral switch instead of the backuplight switch. When I went to look for the plug I had unplugged both, then checked for continuity. One plug didn't have continuity in reverse or neutral. The other had continuity in reverse, but not neutral. I determined that the first must be the speedometer sensor and the second was the backuplight plug, and that the fault must lie somewhere else in teh wiring. That was a bad bad diagnosis.

I repeat, the last sentence above was wrong.

The truth is that neither was the speedometer. The first was for the backup lights, and the second is the neutral switch, which is used to tell the cruise control system if you are in gear. It has continuity in any gear, and not in neutral.

So since I had chosen the wrong switch to work with of course I didn't have continuity between the back up lights and either pin of the plug on the wiring harness that the backup light switch plugged into. So I replaced that wire. Then I found that I didn't have continuity between the fuse box and either pin on that plug. This seemed too odd, but I was almost there, so I just ran new wire there. Actuially I ran wire off the battery to a relay I had lying around, then activated that relay with a line under the dash that gets 12V when the ignition is on.

Voila! they worked. They even shut off when I turn the ignition off and put it ini neutral. Unfortunately they didn't shut off when I put it in gear.

So once I figured out I had the wrong switch, I went back and tested all three wired things coming off the transmission, determined which was actually which by confirming that unplugging the speedometer sensor actually killed the speedometer, and found that the backup light switch was bad. Go figure. I guess I should have just replaced that in the first place. The piece of info that would have saved me all this trouble(well, most of it.) is that the backup light switch is about half way up(heightwise) the drivers side of the transmission and has two red wires. The plug for it is grey. The neutral switch is near the top of the drivers side of the transmission. The plug for it is brown.

Hopefully someone other than me will learn from my mistake,a md when they go to diagnose their backup light switch they will be looking at the right switch.

Have a good one, Bill

Reply to
weelliott

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