Color wiring diagram

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

luna negra

Member
Joined
Jul 3, 2019
Posts
35
Reaction score
25
Location
central texas
First Name
luna
Truck Year
1979
Truck Model
Jimmy
Engine Size
350
Anybody have a colored wiring diagram for a squarebody (1979 K5) where the diagram matches the actual wire colors? I've got a black/white copy and but haven't been able to find one in color like this. For me, these are so much easier to trace things around.

Have a starter that sometimes stays engaged after releasing the key so I suppose it's the solenoid or switch but want to see how it's supposed to be wired before tearing into it. Thanks!
 

chengny

Full Access Member
Joined
Feb 22, 2012
Posts
4,086
Reaction score
1,008
Location
NH
First Name
Jerry
Truck Year
1986
Truck Model
K3500
Engine Size
350/5.7
Anybody have a colored wiring diagram for a squarebody (1979 K5) where the diagram matches the actual wire colors? I've got a black/white copy and but haven't been able to find one in color like this. For me, these are so much easier to trace things around.

Have a starter that sometimes stays engaged after releasing the key so I suppose it's the solenoid or switch but want to see how it's supposed to be wired before tearing into it. Thanks!


The first thing I would check is the condition of teeth on both the ring gear and pinion - but mainly the ring gear. Over the years, some of the teeth on the ring gear may have gotten banged up. This can cause the pinion gear to stay engaged with the RG - even if the solenoid plunger return spring is trying to retract the pinion.

If that is the problem, the ring gear will generally have a few messed up teeth that are confined to a small area of the total circumference. That is why it only happens occasionally

Just drop the starter. First look at the condition of the drive pinion. If it looks okay, rotate the engine and inspect all the RG teeth.

You can view the teeth through the starter mounting opening, but the process goes a lot faster if you drop the flex pate dust cover:

You must be registered for see images attach


How you rotate the engine is up to you, but I just clamp a pair of Vise-Grips on to the flex plate and jack it over. It rotates much easier if you pull a few spark plugs.
 

DanMcG

Full Access Member
Joined
Jun 28, 2014
Posts
1,076
Reaction score
1,884
Location
Central NY
First Name
Dan
Truck Year
1978 1985
Truck Model
k10 k10
Engine Size
400 350
I recently bought a colored wiring diagram from Classic Car Wiring. https://www.classiccarwiring.com/chevytruck/
I won't get around to comparing it to the actual wiring in the 78 till spring to tell ya if it's accurate or not.
 

luna negra

Member
Joined
Jul 3, 2019
Posts
35
Reaction score
25
Location
central texas
First Name
luna
Truck Year
1979
Truck Model
Jimmy
Engine Size
350
Thanks for the tips. I definitely found some of the problems when I dropped the starter, like battery cable burned on manifold, copper posts loose on the solenoid and a ton of dirt and crud packed in the starter and bell housing. Previous owner obviously ran this thing a long time with the inspection cover off. One thing that does confuse me is that there are 3 separate wires and the positive battery cable attached to the main solenoid post. I would have only guessed one wire from the switch and the positive battery cable. Haven't looked at a wiring diagram yet but does this sound normal?
 

DanMcG

Full Access Member
Joined
Jun 28, 2014
Posts
1,076
Reaction score
1,884
Location
Central NY
First Name
Dan
Truck Year
1978 1985
Truck Model
k10 k10
Engine Size
400 350
I think it should be 2 wires. A red to the junction block on the firewall, and a purple to the neutral safety switch under the dash.
 

chengny

Full Access Member
Joined
Feb 22, 2012
Posts
4,086
Reaction score
1,008
Location
NH
First Name
Jerry
Truck Year
1986
Truck Model
K3500
Engine Size
350/5.7
Three leads to the "B" terminal - one BLK from the battery positive and 2 RED's on the system. Also one PPL to the "S" terminal from the ignition switch:

You must be registered for see images attach
 

luna negra

Member
Joined
Jul 3, 2019
Posts
35
Reaction score
25
Location
central texas
First Name
luna
Truck Year
1979
Truck Model
Jimmy
Engine Size
350
Thanks. Will try to get it sorted out this weekend.
 

Forum statistics

Threads
42,116
Posts
909,513
Members
33,611
Latest member
RNFL
Top