No start, no crank, no noise

[Erik Anderson]

Hi this is my first time posting as it is the first time I have not found any help in other threads. I have a 1975 GMC K25, 350, sm465, np205. I am working on restoring the truck from the frame up. I got it back together and running with no problem. I recently removed the dash in order to replace the speedo cable after that it will not start. I have power in the cab as I can hear the heater motor but the starter won't crank over, click, or make any noise at all. I have tried jumping the starter with a section of wire and the engine will turn over so I believe that rules out a bad starter. I've done some some research and my next thought was that the rod from the key cylinder to the ignition switch was broken or the ignition switch itself was bad. I dropped my column down and confirmed the rod does move with the turn of the key. So I assumed the ignition switch was bad, I purchased a new ignition switch and replaced it but I still have the same issue. Power in the cab but the key will not turn the starter over. The last thing I did was confirm that the purple wire at the starter does NOT have power when I have a helper try and start the truck with the key. I am not too good at any wiring on vehicles and completely stuck at this point so any help would be much appreciated. Thank you.

 

[Snoots]

It could be the Neutral Safety Switch. I am assuming a column shift so, with the key in the 'RUN' position move the shift lever several times from one end to the other. You may have to pull up on the lever once you have it in 'PARK' whhile you turn the key to 'START'.

 

[Curt]

It was working before you pulled the dash....pretty coincidental for something just to go bad.I say you have a bad connection or shorted something possibly.Check all your fuses.

 

[deerejohn]

its a manual transmission. clutch safety switch on pedal?

 

[AKguy]

That truck AC equipped? Asking because on the 1981 AC equipped rigs it appears that a separate fusible link feeds the AC/Heater blowers through a relay, enabling the blowers if that link is good when the fusible link feeding your fuse panel could be dead.

 

[Shorty81]

Welcome from Ohio

 

[Erik Anderson]

The truck is a manual so there is no neutral safety switch and there isn't a clutch switch either. I use to be able to put the truck in 1st and it would actually start and take off without pressing the clutch in. I also checked the fuses and they seem all good. There could be a loose connection behind the dash but I didn't really take any apart so I don't even know where to begin. Thank you all for the responses though.

 

[seniorbear69]

check fuse bord power in/out and bulk head plug.my c20 was fine pulled on drive all good went to start dead wiring in my truck is DEATH ! new loom required

 

[deerejohn]

the clutch switch has to be bypassed like mine was. maybe the you wiggled the wire loose while you were in there?

 

[Erik Anderson]

My clutch switch must be bypassed and it is entirely possible I wiggled something loose I will definitely check that. And I pulled the bulk head connector and reinstalled it and everything there appeared fine.

 

[Erik Anderson]

Well it ended up being a loose connection at the clutch switch. Thank you deerejohn for your help. I'll be honest until today I didn't even know my truck had a clutch switch I thought it being able to start in gear was normal so not only was I able to fix my issue but I learned something new.

 

[deerejohn]

awesome. glad you got it fixed.