Post 4 speed swap woes

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.

whiskeydents

Full Access Member
Joined
Nov 23, 2022
Posts
56
Reaction score
222
Location
AZ
First Name
morgan
Truck Year
1976
Truck Model
K25
Engine Size
400
Hello,

First post to the forum, been lurking for the past year or so since I acquired this 1976 GMC K25.
You must be registered for see images attach


Been in the family since it was new. Has the 400, which a local shop just rebuilt. Just finished a sm465/205 swap from the 350/203.

I just got the drivelines back from the shop and it driving again and now the cluster lights only work when the key is in the off position if I turn the headlights on. Once I cycle the key to the run/start position the cluster lights shut off. I also noticed that the fuel gauge and temp sender are not responding. Weird thing is that half the cluster lights up without the headlights/running lights being on.

I pulled the ignition switch and cleaned it, checked wiring on the steering column. Visually checked fuses and they all look good.

Any ideas on what may be going on?

Thanks in advance.

,morgan
 

Strick

Full Access Member
Joined
Nov 25, 2020
Posts
1,105
Reaction score
2,664
Location
Dunn, NC
First Name
Harold
Truck Year
1979
Truck Model
C20 Crew
Engine Size
350
Welcome from NC. That's a beautiful ride.

Strickland
 

Shorty81

Baby Boomer
Joined
Mar 19, 2018
Posts
2,850
Reaction score
5,056
Location
North West ohio
First Name
Darren
Truck Year
86
Truck Model
K20
Engine Size
496
Welcome from Ohio. Gorgeous truck.
 

wanderinthru

Full Access Member
Joined
Jul 23, 2020
Posts
1,170
Reaction score
2,046
Location
Mid Point Route 66
First Name
Shakey
Truck Year
81, 70, 75, 84, 89
Truck Model
K 10, C 30, K 20
Engine Size
350
Hello,

First post to the forum, been lurking for the past year or so since I acquired this 1976 GMC K25.
You must be registered for see images attach


Been in the family since it was new. Has the 400, which a local shop just rebuilt. Just finished a sm465/205 swap from the 350/203.

I just got the drivelines back from the shop and it driving again and now the cluster lights only work when the key is in the off position if I turn the headlights on. Once I cycle the key to the run/start position the cluster lights shut off. I also noticed that the fuel gauge and temp sender are not responding. Weird thing is that half the cluster lights up without the headlights/running lights being on.

I pulled the ignition switch and cleaned it, checked wiring on the steering column. Visually checked fuses and they all look good.

Any ideas on what may be going on?

Thanks in advance.

,morgan
It's a weasel, damn electrical weasel! Nice truck and good swap btw. Did you take the dash instrument cluster etc out to put the clutch pedal in?
 

whiskeydents

Full Access Member
Joined
Nov 23, 2022
Posts
56
Reaction score
222
Location
AZ
First Name
morgan
Truck Year
1976
Truck Model
K25
Engine Size
400
It's a weasel, damn electrical weasel! Nice truck and good swap btw. Did you take the dash instrument cluster etc out to put the clutch pedal in?
Thank you, no I did not, pulled the seat and dropped the column.
 

whiskeydents

Full Access Member
Joined
Nov 23, 2022
Posts
56
Reaction score
222
Location
AZ
First Name
morgan
Truck Year
1976
Truck Model
K25
Engine Size
400
I am also trying to get the ignition switch/steering column wiring routed in the original location, if anyone has a picture of how theirs is routed, it would be appreciated.

Thanks
 

whiskeydents

Full Access Member
Joined
Nov 23, 2022
Posts
56
Reaction score
222
Location
AZ
First Name
morgan
Truck Year
1976
Truck Model
K25
Engine Size
400
Disregard the initial question of the thread, I found that the cluster plug was loose after I had screwed around with the column wiring and what not. Keep it simple, stupid. Wouldn’t mind if someone would snap a picture of their column wiring routing though.

Morgan
 

whiskeydents

Full Access Member
Joined
Nov 23, 2022
Posts
56
Reaction score
222
Location
AZ
First Name
morgan
Truck Year
1976
Truck Model
K25
Engine Size
400
Thanks for the picture but I’m looking for how the harness snakes it’s way around the column once it’s installed, I don’t know if how I have it is how it should be. Not a huge deal but would be nice to get it set right.
 

Originalthor

Full Access Member
Joined
Aug 22, 2021
Posts
1,015
Reaction score
3,386
Location
Saskatoon Saskatchewan
First Name
Scott
Truck Year
1989
Truck Model
Suburban
Engine Size
5.7
You must be registered for see images attach


This shot is from the drivers side vent towards the steering column. On mine the ignition wires and brake lights switch goes over top of the column. I remember making the mistake of bolting in my column then running the wires after and had to unbolt it to get the wires up over and plugged in.
 
Last edited:

Latest posts

Forum statistics

Threads
41,859
Posts
903,668
Members
33,372
Latest member
83elcowes
Top