Goin' nuts trying to figure out the wiring on my truck. If I turn on the hazards all the parking lights blink, even the clearance lights on the roof. The 4 grounds at the corners are good. If I turn on the parking lights the turn signal indicators in the dash light up. I think the switch in the cloumn might be shot. The light blue wire is the power to the switch, when I touch it to the turnsig. wires BOOM! they work. I am assuming the switch is shot but the whole harness was spliced together so I am taking it that a new column was put in at one point in time. But what really baffles me is why all the parking lights flash when I hit the hazzards. Thanks for any input.


Hey the EDIT button works.

EDIT:
.When I hit the parking lights the turn signals light up also(both bulb filaments) I'd rather rip the motor out than #$&! with wiring. Thanks.

 

Get a wiring diagram, they are available from the online store here for a nominal charge with the OEM service manuals on CD. Bad grounds are also a common problem.

 

Got a diagram, all of the grounds check out???

 

All I can say then is to trace out the wiring. There is no magic to it.

 

I have a new switch for my 77' f-150. its eazy to replace. you just need to pull the wheel and remove the old. the switch has all the wires attached already and it gets spliced in under the dash near the steering column (so what you said you have is normal)

 

There is a very good tech article (link at top right of page) about testing a trouble shooting light wiring problems. Read through it and do the testing on your pickup. Try to eliminate one thing at a time to narrow down the possibilities. Let us know what you find.

Marty

 

Well, here goes. Tore the heck outta my truck and I found a wire that had melted and the only other wire it seemed to take out was the wire going to the horn relay. The wire that melted was green/yellow but it dosent show on the schematic. Well it does but the schem. shows it as the door switch wire, but it's running through the firewall? I replaced the turn signal switch and now I have both turn signals with the parking lighs off. If I turn the park lights on I only have a left turn that blinks slow. If I plug in the instrument cluster it blinks a little faster. I ran new grounds (grinder to bare metal and a self tapping screw) from the intake to the body and the frame (2 wires) and in the back from the frame to the bed. I seem to be making progress but still a liitle more to go. I'm thinking maybe a bad light switch now but I believe the circuits (turn and park) are seperate. Could the instrument panel have a short? Does anyone know what the green/yellow wire could have been for? It seemed to disappear in the engine compartment part of the wire harness. I put the continuity tester on any wirs in question and they all checked out so I'm lost again? Oh well. I need to get this thing on the road. I bought a house and had to sell my truck (03 Ram) I'm sure all you guys love that one! Thanks in advance.

 

you have trouble in the column wiring get a manual and a test light and ohm meter pull the steering wheel and ring out the wiring grn/yellow should be dome courtesy lamps blue\red is dash lamps there is more than one harness for the steering columnms on 73-79 fords and sometimes the colors dont match

 

The Green/Yellow wire I know of is for Courtesy lighting (to Glove box ,Vanity Mirror)

This would be easier of you had pics for us

 

I know it's been a while but I got everything working somewhat. When I turn on the p/k lights the turn lamps in the dash light up. With the p/k lights offf the signals blink fast. With them on .....slow. Any I deas? This is a daily driver now so I'd like to egt her runnin'

 

Hey Powpusher,You were right but I didn't read your post in time. The Yel/Grn IS in fact to the door switch. However when it melted down the previous owner did not take the proper steps to correct it. Thannks anyway!!! IW3

I LOVE that old truck!!