I'm needing to flat tow my '79 F-150, and the only thing thats giving me trouble is how to wire the lights so I can plug into the factory rear harness on my '79. I would like to somehow tap into the rear wiring harness that goes to the lights, and run a cable up to a plug on the front of the truck. Then when I'm ready to flat tow, all I'd have to do is plug in a double ended cable (one end into the plug on my F-250, one into the front of the F-150) and go.

My questions are:

1. Can I just tap directly into the wires for turn signal and brake lights, or would back-feeding the system be bad?

2. For the tail-lights, if I tapped directly in I assume it would also make the headlights come on as well (or at the very least the parking lights), which would be bad. Any way around this?

3. Last question is somewhat un-related, but for an 80mi tow on the interstate should I disconnect the rear D-shaft, or just throw the tranny/t-case in neutral (i.e. is there an input driven pump on either which wouldn't spin and therefore mess things up)? See sig for drivetrain.

Thanks for any advice.

I'm needing to flat tow my '79 F-150, and the only thing thats giving me trouble is how to wire the lights so I can plug into the factory rear harness on my '79. I would like to somehow tap into the rear wiring harness that goes to the lights, and run a cable up to a plug on the front of the truck. Then when I'm ready to flat tow, all I'd have to do is plug in a double ended cable (one end into the plug on my F-250, one into the front of the F-150) and go.

My questions are:

1. Can I just tap directly into the wires for turn signal and brake lights, or would back-feeding the system be bad?

2. For the tail-lights, if I tapped directly in I assume it would also make the headlights come on as well (or at the very least the parking lights), which would be bad. Any way around this?

3. Last question is somewhat un-related, but for an 80mi tow on the interstate should I disconnect the rear D-shaft, or just throw the tranny/t-case in neutral (i.e. is there an input driven pump on either which wouldn't spin and therefore mess things up)? See sig for drivetrain.

Thanks for any advice.
What you need are diodes. They are fairly common, 2 in and 1 out. This way the electrical signal won't back feed into the rest of the system. You'll need 3 of them. One for each of the turn signals (which are also the brake lights) and one for the running lights. Most kits come with four diodes (for a seperate brake wire, like Toyota's) but you won't need that. It is a good idea however, to get the four pack kit and keep the one for a spare, I have seen them die before (don't know why really).

I don't really have any experience with a 205 so I couldn't give you a good answer, sorry.

What are the specs on the diodes that I'd need? I assume I would need to get these at radio shack or a place like that?

What are the specs on the diodes that I'd need? I assume I would need to get these at radio shack or a place like that?

Your local RV center should have an ample supply of diode units.

An example (http://secure.ultracart.com/catalog/rvtoy/towing/wiring/RM150.html)

Yep... did this to my YJ just to have an extra set of lights while it's on the trailer. RV supply... about $11/diode.

Does the truck you are towing have a trailer plug?? If it does I would plug into it and to keep from back feeding I would pull the fuses..

I just put a toggle switch on one of the tail light wires upstream of where the connection is. When I flat tow, I just flip the toggle swith to create an open circuit so there can't be any back feeding. Hope this makes sense.

hy_desert_4wheeler Does the truck you are towing have a trailer plug?? If it does I would plug into it and to keep from back feeding I would pull the fuses..
JHarsany I just put a toggle switch on one of the tail light wires upstream of where the connection is. When I flat tow, I just flip the toggle swith to create an open circuit so there can't be any back feeding. Hope this makes sense.
Both these ways would work, so please don't take this bad.

You can do either one of the ways mentioned, but the diodes would be considered to be the correct way of doing it. The other ways accomplish the same thing, but with the diodes, you do the work once and that is it. Each time you tow after that it is a simple plug and tow. Please don't get mad, if he was only going to flat tow one time, and one time only, then removing the fuses might be the answer. But if towing more than once then the switch or diodes would be the answer. The switch and diodes would take about the same amount of work, so IMHO why not just put in the diodes.

VerticalTRX, if you have trouble finding the diodes let me know and I'll make sure to get you hooked up with everything you need.
Aaron