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73-87 Chevy _ GMC Trucks => Electrical => Topic started by: 1979stepside on July 19, 2014, 01:28:43 pm

Title: 79 c10 no crank
Post by: 1979stepside on July 19, 2014, 01:28:43 pm

Hello All

Ill try to give as much detail as possible (recent past and current)

79 C-10, unsure if it’s a 305/350, automatic on tree. Recently (about two months ago) had problems with blown distributor and cracked pin on rotor that was replaced, old stock new radio installed about a month ago that got very hot on one side.

Currently need some help, Truck ran fine for about a 15 min trip, shut it down, 1 hour later – no crank.

Will not crank over, no clicking at all (kinda like there is no battery) but there is a fully charged one that is properly connected. No power at the radio, signals, power windows or wipers etc. Headlights and interior lights work fine.

I checked the fusible link at the starter and it has power on both sides of it.

While searching around I seen a yellow wire that comes off the ignition switch (mid of steering column) and it goes to nowhere. There is another yellow wire (very similar in size, colour, fading etc) that comes out of the reverse back-up switch/module (bottom of steering column). It also goes nowhere, I tried to connect these wires together and nothing changed. Then  I got a little more adventurous with the yellow wires and I placed the open reverse backup side into the “constant “ in the fuse box and the engine turns over (with key in off position) but will not start, just cranks? I’m pretty sure these yellow wires were like this before the current problem happened anyway.

Also replaced ignition switch, (yellow wires still going nowhere) no difference.

Any ideas, detailed help is appreciated

Thanks

Title: Re: 79 c10 no crank
Post by: bd on July 19, 2014, 02:35:32 pm

Refer to the 1979 Wiring Manual (http://www.73-87chevytrucks.com/techinfo/7387CKMans//Wiring/ST_352_79_1979_Chevrolet_Light_Truck_Wiring_CK_10_30_Only.pdf).

The yellow wire from the ignition switch connects to the neutral safety switch (auto trans) or clutch interlock switch (manual trans), changes to purple and runs out through the firewall bulkhead connector to energize the starter solenoid.  Always be alert to the possibility that someone may have altered the original wiring.

Check the two fusible links at the firewall junction block above the back of the motor.  The ignition switch receives battery power from that junction.  If all the links are in good shape, check the 12-gauge red feed wire through the firewall bulkhead connector and trace back to the ignition switch as necessary.

Title: Re: 79 c10 no crank
Post by: 1979stepside on August 05, 2014, 01:11:35 pm

Thanks, Fusible links needed some adjustments :)

Title: Re: 79 c10 no crank
Post by: RustyChevrolet on October 28, 2014, 09:04:46 pm

1979 stepside,   what fusible link was it that needed adjustment. My truck is giving me the same problems right now.