69 D100 318- no start from key, starts from solenoid

[Noelie84]

Morning All.
Took the truck to the store yesterday and when I got back to the truck it wouldn't start from the key. Switch it to 'run' and all of the dash turns on, radio works, fan works, etc. But nothing at all when I turn it to 'start'. So I set the parking brake, put it in Neutral, made sure the key was turned to 'run' and grabbed a screwdriver out of my 'road emergencies' kit. Jumped the solenoid on the fender and she fired right up.
Drove it home and parked it, shut it off, and same thing; nothing when you start it with the key.

I'm 98% certain that I can test to see if it's a problem with the switch or the wire by jumping the terminal marked 'BAT' to the terminal marked 'ST' with the key set to 'run' (if it starts it's a switch problem, if not then it's in the wiring). But I figured I'd ask the Brain Trust before I turned out to be wrong and toasted a perfectly good ignition switch

[dodgeboykim]

Does starter Sol get 12 V signal from Ign switch in start position. Guessing you have a standard trans. Is Sol correct one for standard or has some one jury rigged an Auto Sol in its place.
Auto ones have a neutral safety position and would need to be grounded.

Testing at ignition switch may be necessary.

[ozzie]

bad solenoid! had that problem before. started when jumping just like you, replaced the solenoid fixed it.

[Noelie84]

I appreciate the responses, but nobody's answered my question...
All I need to know is what wire to jump on the back side of the key switch to test whether the problem lies with the key switch, the solenoid, or the wiring between them.

Does starter Sol get 12 V signal from Ign switch in start position. Guessing you have a standard trans. Is Sol correct one for standard or has some one jury rigged an Auto Sol in its place.
Auto ones have a neutral safety position and would need to be grounded.

Testing at ignition switch may be necessary.

It has the correct manual transmission solenoid (two stud terminals and 1 blade) and not a jury-rigged auto solenoid (2 studs and 2 blades), which appears to be quite old. However, the key switch itself is probably just as old, just less exposed to the elements. Unfortunately I'm a one man show at the moment; the GF is out of town for the next few days so I've got nobody to hold the key in 'start' mode while I test the wire at the solenoid.

bad solenoid! had that problem before. started when jumping just like you, replaced the solenoid fixed it.

Yeah, the solenoid is 1/3 of what the problem could be (key switch and wiring being the other 2/3). I'm not looking to just throw parts at it, though, even if we are just talking about spending $10 vs $20. So I'm hoping somebody can tell me what wires (for sure) need to be jumped to bypass the key switch, so I can see if the fault lies on that end, or if it's further 'downstream'

[PwrWgnDrvr]

Morning All.
Took the truck to the store yesterday and when I got back to the truck it wouldn't start from the key. Switch it to 'run' and all of the dash turns on, radio works, fan works, etc. But nothing at all when I turn it to 'start'. So I set the parking brake, put it in Neutral, made sure the key was turned to 'run' and grabbed a screwdriver out of my 'road emergencies' kit. Jumped the solenoid on the fender and she fired right up.
Drove it home and parked it, shut it off, and same thing; nothing when you start it with the key.

I'm 98% certain that I can test to see if it's a problem with the switch or the wire by jumping the terminal marked 'BAT' to the terminal marked 'ST' with the key set to 'run' (if it starts it's a switch problem, if not then it's in the wiring). But I figured I'd ask the Brain Trust before I turned out to be wrong and toasted a perfectly good ignition switch

Test it as u said above. If it starts its the switch. If not, its the wiring or the solenoid.

From experience, its most likely the switch. The contacts inside it build up carbon over the yrs until they no longer conduct electricity. Ive disassembled the switch and cleaned the contacts, but its not a task for the faint of heart.

[Noelie84]

Morning All.
Took the truck to the store yesterday and when I got back to the truck it wouldn't start from the key. Switch it to 'run' and all of the dash turns on, radio works, fan works, etc. But nothing at all when I turn it to 'start'. So I set the parking brake, put it in Neutral, made sure the key was turned to 'run' and grabbed a screwdriver out of my 'road emergencies' kit. Jumped the solenoid on the fender and she fired right up.
Drove it home and parked it, shut it off, and same thing; nothing when you start it with the key.

I'm 98% certain that I can test to see if it's a problem with the switch or the wire by jumping the terminal marked 'BAT' to the terminal marked 'ST' with the key set to 'run' (if it starts it's a switch problem, if not then it's in the wiring). But I figured I'd ask the Brain Trust before I turned out to be wrong and toasted a perfectly good ignition switch

Test it as u said above. If it starts its the switch. If not, its the wiring or the solenoid.

From experience, its most likely the switch. The contacts inside it build up carbon over the yrs until they no longer conduct electricity. Ive disassembled the switch and cleaned the contacts, but its not a task for the faint of heart.

And do you know if jumping the 'BAT' terminal to the 'ST' terminal would be the best way to bypass the key switch?

[PwrWgnDrvr]

If u want to test the switch only, and not include the wiring from the switch to the relay, then the only way to do that is jumping the terminals on the switch.

[ozzie]

Morning All.
Took the truck to the store yesterday and when I got back to the truck it wouldn't start from the key. Switch it to 'run' and all of the dash turns on, radio works, fan works, etc. But nothing at all when I turn it to 'start'. So I set the parking brake, put it in Neutral, made sure the key was turned to 'run' and grabbed a screwdriver out of my 'road emergencies' kit. Jumped the solenoid on the fender and she fired right up.
Drove it home and parked it, shut it off, and same thing; nothing when you start it with the key.

I'm 98% certain that I can test to see if it's a problem with the switch or the wire by jumping the terminal marked 'BAT' to the terminal marked 'ST' with the key set to 'run' (if it starts it's a switch problem, if not then it's in the wiring). But I figured I'd ask the Brain Trust before I turned out to be wrong and toasted a perfectly good ignition switch

Test it as u said above. If it starts its the switch. If not, its the wiring or the solenoid.

From experience, its most likely the switch. The contacts inside it build up carbon over the yrs until they no longer conduct electricity. Ive disassembled the switch and cleaned the contacts, but its not a task for the faint of heart.

I think that you are overthinking this, I would bet it is the solenoid, it is the thing that will go first before the ing. switch. it is more exposed, and has to take more use than the switch. Ozzie.

[PwrWgnDrvr]

Morning All.
Took the truck to the store yesterday and when I got back to the truck it wouldn't start from the key. Switch it to 'run' and all of the dash turns on, radio works, fan works, etc. But nothing at all when I turn it to 'start'. So I set the parking brake, put it in Neutral, made sure the key was turned to 'run' and grabbed a screwdriver out of my 'road emergencies' kit. Jumped the solenoid on the fender and she fired right up.
Drove it home and parked it, shut it off, and same thing; nothing when you start it with the key.

I'm 98% certain that I can test to see if it's a problem with the switch or the wire by jumping the terminal marked 'BAT' to the terminal marked 'ST' with the key set to 'run' (if it starts it's a switch problem, if not then it's in the wiring). But I figured I'd ask the Brain Trust before I turned out to be wrong and toasted a perfectly good ignition switch

Test it as u said above. If it starts its the switch. If not, its the wiring or the solenoid.

From experience, its most likely the switch. The contacts inside it build up carbon over the yrs until they no longer conduct electricity. Ive disassembled the switch and cleaned the contacts, but its not a task for the faint of heart.

I think that you are overthinking this, I would bet it is the solenoid, it is the thing that will go first before the ing. switch. it is more exposed, and has to take more use than the switch. Ozzie.

Ozzie, please clarify.
The solenoid is on the starter, and is operating correctly since the truck starts by jumping.
The starter relay is on the inner fender. By definition, it is not a solenoid.
Which one are u referring to?

[ozzie]

My bad, it is the relay on the inside of the fender, sorry.

[Wildergarten]

My bad, it is the relay on the inside of the fender, sorry.

The relay is a frequent problem. The easiest thing to do is to jump the bat terminal to the solenoid line with a screwdriver. If that kicks the solenoid, it's either the relay or the switch wiring (my vote on the latter is the firewall plug). The next test is to get an assistant to throw the key switch to "start" and look for voltage at the incoming wire. Lacking that, I'd pull the plug off the key switch, note which lugs are to the ignition and the relay. Look for a 12V supply on the unswitched leg. If there is 12V, I'd plug it back in and look for 12V coming out the correct lugs on the back (stuff the probe into the connector body). Unless my recall is flaky, there are TWO (2) switched 12V outputs (to keep the current under limits at the contact set inside the switch) and yet another for the starter relay and ballast resistor. If it all of that is working (and it probably is), you're back to the firewall plug.

[WD]

Search older posts on this subject. There was a complete tutorial to convert to a Ford relay. It completely solved the same issues on anther member’s truck. Heavier duty components.

[Kaegi]

Search older posts on this subject. There was a complete tutorial to convert to a Ford relay. It completely solved the same issues on anther member’s truck. Heavier duty components.

the ford type relay is what they used on my D300s on most that I can remember anyway. it really isn't a ford relay it is a type that ford and dodge uses. they are very common in machinery.

[Noelie84]

Just realized I'd never followed up on this.
In answer to my original question, jumping 'BAT' to 'ST' IS how you bypass the key switch. Which really was all I needed to know, but thanks to everybody who gave me all of the other answers besides that one

I checked continuity on the wiring and there were no interruptions between the switch and the fender relay, so I ordered a new fender relay (Manny Tranny, so Standard part #SR103) from Rock Auto. Popped it in and she fired right up. No problems since then.