I am posting with the hopes that someone has a simple solution. The most recent truck to follow me home has some lighting issues. It's a tow truck so it has lots of extra lights on the bed, crane and tow body. When you step on the brakes with the switch off the dash lights up along with the running lights on the bed and what looks like the running lights on the crane and the rear end. When you turn the lights to running lights the same but no brake lights when the petal is depressed. The headlights come on only when the switch is pulled out all the way. Turn signals function fine and flash on what appears to be the bright part of the bulb. Brake lights do not work when lights are on.

The only thing I have done so far is swap out the headlight switch with no luck.

There are no splices under the hood or dash. Under the tow body it's a whole different story. There are a ton of wires that go up to the lights on the crane. Some of this is for the flashing lights and rear facing spots for use when hooking up. Somehow the reverse lights are hooked up with some spotlights under the tow body that come on with a switch or while in reverse. I would imagine that the reverse lights have nothing to do with anything as they are not through the headlight switch.

The cab top lights do not come on at all. I have not bothered to check bulbs

Anyone have a quick fix solution?

 

I have never worked on anything with so many bulbs. I can only imagine that having a sub circuit to operate all the extra lights would be in order.

For the truck excluding the extras, pull the light switch one click = parking lights on the front, tail lights, license plate lights, on the rear.

Pull out fully you basically change front only from parking to headlight. Older models, the front parking lights go away.

There are 3 wires going to the rear, green, brown & yellow. With the first click, parking lights on front, taillights on rear.

The two remaining wires to the rear are brake, left & right turn signals that share the same filament in the bulb.

Tail lights on, one wire glowing, brake on both burning, add turn signal the second pulses off & back on.

Someone else will have to help you with the extras, they can be triggered by the switch to come on but need a pay grade higher than mine to detail.


guluk




John

 

whew...yeah, that's going to be a mess.

i would guess that somewhere under the tow body, there is a splice between a brake light wire, and the circuit that runs all those extra lights that are coming on when you step on the pedal. interesting that somehow the dash lighting is tied in, as well.

i would look under the dash- try to find the wire that is spliced in and causing the dash lights to come on when you step on the brake. then follow that back to wherever it is connected.

this should be fun.

 

I have a feeling this is going to be fun.

Once I get into this I think the best thing to do is cut all the extra stuff on the tow body then start adding it back testing with a hot wire to see where each wire goes.

I have never owned anything with cab top lights. Do they come on with the first click or second and do they and if they come on with the first click do they stay on with the second? Does the wire that feeds them run along the path of the dome light and gas tank sender wire? Is there a relay for them somewhere under the dash that may be bad?

 

As jowilker said

Pull one click = parking/running lights (whatever you want to call them) & this includes any cab top lights - should be all lights except for the headlights, bright rear brake lights(low brake/tail lights should be on) and of course any clear reverse lights.

Pull 2 clicks = click one lights stay on and headlights are added to the list of lights on.

Now the tricky part is 67 to I think 69 (maybe 70) the front parking/running lights under the headlights will turn off when the headlights are turned on (2 clicks out).
All later years the parking/running lights under the headlights stay on with headlights. So as you pull the headlight switch out you just keep adding lights to the list of "ON"

If you decide to just give up and start from scratch use relays. It helps to save the switch and gives you brighter lights.

Wiring can always be frustrating. And with this many lights..... WOW....
Personally I would probably do a Google search for Tow Bed wiring buy about a thousand feet of wire and just start over from the cab back.

Good luck

 

I'm with ya there. I'd unload all the circuits/wiring (not necessarily cut) and to isolate and get all the "truck" systems working. Then add another fuseblock and relays for systems associated with towing.....A 3G alternator and dual battery system would be nice upgrades.

I almost bought a tow truck last year but alas it was the wrong make (Bowtie).. 454, TH400, and a dually 14-bolt for $1000... smog exempt too. It'd be a hoot driving pulling up to the office with tow truck.

 

It's been there. Everyone knew who it belonged to without asking. Most did ask why.

I was going to get the 500 foot roll and pray...

I still would like to know about the cab top lights. Is there a relay? If so where?

I did speak to someone at Weld Built today. I asked about the lighting. I was told by one of the short timers (27 years) that they plugged into the tail light wiring for the rear body lights and the crane tower lights. I also asked if all the bodies came with Ford tail lights on the crane. I was told that all they did was remove the ones that came on the bare chassis and move them up. He said the lights on the sides of the tow body were added by a PO. Some people will be spending Christmas day with family and friends but I will be spending it with my tow truck! Soon my wheels will be back from the powder coater and I can start driving around on all 6 tires!

 

I have never owned a truck with cab top lights, but agree with 7283-F250 & others, they should come on with all other lights. There should be a single wire coming in to the dash area from the top. All vehicle lights are body ground return so there is no return wire to find like house wiring.

Adding relays is also a good idea. I would suggest you read the Brighter/Whiter lights article to learn how they help. I added the relays to my truck and it stopped my headlights from blinking off. Whiter Whites, Brighter Brights .: Articles

I might use a hot wire connected to the battery to test circuits with at the rear. Just keep the end covered while not testing since it is not fuzed.


guluk




John

 

I think the cab lights would just be wired into the running lights somewhere.

I could be wrong but I do not think there is a single relay on 67-72 F-Series. I am pretty sure my 68 and 72 F250's do not have any. They also do not have cab lights.

 

My Camper Special has a little relay under the dash on the passenger side. It is fed by a different and heavy feed wire from the Starter Selenoid. I think it takes some of the load off the headlight switch wiring, and provides for the cab lights. (Mine aren't installed). Does anyone know more about it?