I have a 1986 Ford f150 with automatic c6 tranny. I have problems with the backup light lights staying on. When I shift the gear selector a few times slowly sometimes the lights come on..sometimes they do not. I looked under the truck on the side of the tranny and I see a few wires going to some plastic piece behind some metal round part with a few bolts which hold the gear selector lever mechanisms. Is this the switch? Can you make any adjustments? Need some help and diagrams and photos if possible please.

 

I forgot to mention it is just a normal 3 spd automatic c6 with no overdrive

 

LMC sells backup light switches:

LMC Truck Parts - Page 152

I replaced mine (different tranny), remarkably easy to do. There's a nylon switch/button that wears down - it should protrude from that threaded end about 1/2". Mine looked like this - the button was completely gone:

 

willeyJoe. Where is that switch located. I think you may have solved my issues as well as shortblock2000's with that answer.

 

I know it's different on different transmissions. All you have to do is find the wiring that leads to the transmission, and there it is. On my T170F 4-speed OD, it plugs in at the upper rear of the tranny. The line runs along the frame under the driver's door, then along a crossbeam. Unplug the wire at the switch, loosen the switch with a wrench, unscrew it, and there it is. One of the easiest things I've done on my 81 F100, and a very simple solution - I had no backup lights whatsoever. Methinks this is a fairly common problem, as those backup switches are pretty easy to find - they must sell a lot of 'em.

Here's a shot when I was scrubbing down my transmission a few weeks ago - the red arrow points to it. I'd already replaced it and covered the line in a new corrugated shroud.

TIP: Pull your old one and get a look at it before you order a replacement. I successfully ordered the wrong one the first round, and had to return it.

 

The reverse lights are part of the neutral safety switch on the C6 transmission, are they not? I haven't been under the truck to check, but I believe there are four wires involved.

 

If youre in a pinch pushing the heat lever back and forth while it's in gear may make contact.

 

That's what I thought, too, but it turns out this is true for 1983+ trucks only, 80-82 had separate switches:

https://www.ford-trucks.com/forums/1...l#post11749087

BTW I have no idea what year of truck we're talking about here in this specific case, just wanted to say that the 4-wire switch scenario doesn't apply for everybody.

 

Ah, yes, the beloved 81. Such a sweet, simple era, when men were men and giants roamed the plains ... The last great year, with letters on the hood...

 

Ahh, and the swiss cheese frames for better mpg and to keep the EPA off Ford's back. This was the guilded age.


Also I believe the back up lamp switch on the C6 is part of the nuetral safety switch. That is the only mechanism that has wires going to it as far as the tranny is concerned. I know the column and the shift indicator have nothing attached to them to operate a back up lamp.

I dont think the switch is adjustable either. It probably just takes a new switch to rectify the problems. I am willing to bet any parts store carries them.

 

The C4 and C6 transmission mounted switches are adjustable. There is a small hole through the switch that I think a paper clip will fit in. Put it in neutral, find the hole and if the paper clip wire will go in a fair distance then you are probably adjusted right and need a new switch. If it won't go in, loosen the hold down bolts until it will move and align it.

If you need to replace it, you have to remove the downshift lever in order to get the switch off. Be careful not to lose the O-ring in the shift lever! You will probably have to hold the end of the downshift shaft when you reinstall the lever.

 

Huh. Well, that's good to know, given that my 1980 needs a new one.

Thanks for the info.

 

How do you know how far to stick the paper clip and what are we actually pushing with the clip? Also what is the correct alignment with the switch? Are there any marks? A few photos would sure help if anyone can post?