75 ignition
Thread Starter
|
Junior User
Joined: Oct 2003
Posts: 60
Likes: 0
75 f100 ignition
Just recently i got a 75 f100 to fix up. the guy i got it from said that the ignition switch was bad, so i went and bought a new switch and lock cylinder. the truck still would not start without jumping the starter relay terminals. Just yesterday i had to go get another relay b/c the old one (which wasnt that old) had finally burned up. when i turn the key to start the truck, theres nothing, not even a click. i am having trouble locating where the wires go from the switch. can someone please help me and tell me where to look for the problem.
Last edited by slntnddly; Oct 26, 2003 at 11:19 AM.
Posting Guru
Joined: Sep 2003
Posts: 1,192
Likes: 1
From: lino lakes, mn
is it an automatic tranny if it is check the neutral safety switch on the steering column another thing to look at is the wires on the starter solinoid they could be backwards red/;wblack tracer goes to the s terminal do you have a manual if not get one the Haynes has good wiring diagrams in it and as clear a discripitions as the rest any time you buy something to fix up stop on the way home and get the manual even the best mechanics use them they have to
Thread Starter
|
Junior User
Joined: Oct 2003
Posts: 60
Likes: 0
it is an automatic tranny, and i do have the haynes manual. i have checked the wiring on the solenoid and it is correct. if the neutral safety switch was bad, would the truck still start by jumping the terminals?
Thread Starter
|
Junior User
Joined: Oct 2003
Posts: 60
Likes: 0
75 f100 ignition wiring
i just recently got a 75 f100. when i got the truck the guy showed me how to jump the terminals on the starter solenoid and told me that the switch needed replacing. After buying a new switch and cylinder, still nothing. Yesterday, the old (still new condition) solenoid burned out. i went and bought a new one and still doesnt work. i have been looking at my haynes manual trying to trace the wiring diagrams but i am having trouble understanding them. can someone please tell me where the wiring goes from the switch so that i can trace down the problem.
1975 ford f100
automatic tranny
302 engine
1975 ford f100
automatic tranny
302 engine
Moderator
Joined: Jan 2001
Posts: 56,971
Likes: 2,731
From: Virginia
The only diagram I have access to is a 76. Here it is.
http://www.cybrrpartspro.com/Chilton.../85766101L.gif
Let's assume this part of the wiring will be the same for your year truck. I know it uses the same color wires as my later truck.
Look in the middle of the diagram and there is a red/green coming out of the ignition switch that says "to starter relay". This is the wire you want to look for. But what this diagram doesn't show you(did I mention the diagram I have access to is pretty lousy?), is after coming out of the switch, this wire goes to a neutral safety switch. This will be a switch on the clutch pedal if it's a manual, or a switch on the side of the tranny if it's an automatic.
Did the previous owner change the engine and transmission in this truck? If he went from an auto to manual tranny, or manual to auto, he might have left the original red/green neutral safety switch harness hanging, and this may be why it won't crank over. If you find these two wires hanging around somewhere, jumper them together and see if the key will crank the engine.
http://www.cybrrpartspro.com/Chilton.../85766101L.gif
Let's assume this part of the wiring will be the same for your year truck. I know it uses the same color wires as my later truck.
Look in the middle of the diagram and there is a red/green coming out of the ignition switch that says "to starter relay". This is the wire you want to look for. But what this diagram doesn't show you(did I mention the diagram I have access to is pretty lousy?), is after coming out of the switch, this wire goes to a neutral safety switch. This will be a switch on the clutch pedal if it's a manual, or a switch on the side of the tranny if it's an automatic.
Did the previous owner change the engine and transmission in this truck? If he went from an auto to manual tranny, or manual to auto, he might have left the original red/green neutral safety switch harness hanging, and this may be why it won't crank over. If you find these two wires hanging around somewhere, jumper them together and see if the key will crank the engine.
Posting Guru
Joined: Sep 2003
Posts: 1,192
Likes: 1
From: lino lakes, mn
the neutral safety switch is on top of the steering column on a 75 it is a slide switch it comes off with two screws you could try jumping the wires to see if you can get it to start with the key there or go up to left side of the column (follow the wires) unplgit and jump it there
