Cluster is overwhelming

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SquareBodyGirl75

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Michelle
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1975
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gmc
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5.7
Hey all. I have a 1975 gmc k25 that I have been working on for a few now.
I’m working on the wiring under my dash to the fuse panel. Half of my things work and some work on their time and she kept blowing fuses. Well u took the dash off and noticed so many wires and loose connections that I have lost myself in the ordeal. Can some guide me to any site that would dumb it down with sections at a time to help me get it figured out? Yes the plan is to eventually by all new wires and upgrade my fuse panels. However I just did other work to her and just need her to run for a sparingly moment. Anything helps. Thanks
 

sickchev

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Jason
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1979
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c20
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5.7
That's a tough situation. The best bet is to get a wiring schematic for the truck and start getting familiar with the factory setup. You will need to know the core wiring to figure out if someone added stuff over the years. The folks on this site are always willing to help if you put up pictures of some confusing parts.This video helped me when i was first starting to identify what goes where. I hope this helps.
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Chevy 88

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.

Someone said it was a fire hazard, but what the hell do they know....

Here is the way I did mine:

.
 

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EvilGenius

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Grab a wiring diagram from the tech section. If you can't locate one for your specific year just look for adjacent years, GM didn't really change the wire colors or how they did things much year to year. That may not be true with the big change at 1980 so stay on your side of that split if you can't find your exact year.

To help simplify how to understand the circuits in the truck they fall into two types: switched power and switched ground. What this means is that some circuits have constant or keyed voltage on one side and are waiting for a ground (engine temp works this way, the sender is the ground and varies the resistance) or the circuit has a constant ground and is waiting for a voltage to be applied (the dash lights work this way).

For each item you're having an issue with identify which color wire it is and line that up with the manual. Then start tracing and check continuity as you go.
 

SquareBodyGirl75

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west jordan
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Michelle
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1975
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gmc
Engine Size
5.7
That's a tough situation. The best bet is to get a wiring schematic for the truck and start getting familiar with the factory setup. You will need to know the core wiring to figure out if someone added stuff over the years. The folks on this site are always willing to help if you put up pictures of some confusing parts.This video helped me when i was first starting to identify what goes where. I hope this helps.
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Thank you a bunch. I had been fed up with that wiring for so long not to mention it was the first fire truck from teoole utah so it has had a lot of modifications done to it. I did buy a new harness and fuse panel and I’m hoping and praying that it’s not a couple week job as that’s what I have spent doing just the wires it self that’s not completed yet. I just want to start her and hear her. This is my baby and sadly it’s been rough not having her around yet I have to look at her every night and first thing in the morning in a parking stall looking beautiful. Any easy suggestions that could help me I would be open to. It’s me and me only no other person is to help so short simple steps would be best lol
 

Broken85

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K10
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These may help you start your di-ag. (Yes, I stole these like a thief in the night). A good test light and multimeter are essential. Sounds like you probably need to start from scratch. Also don’t forget to check power from the battery to the starters and to the alternator and finally from the starter to the fuse panel first since that is where power for the whole truck starts from. A lot of people chase gremlins because someone got creative powering the fuse panel “a better way.” Once you are 100% under the hood, then start under the dash.
 

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SquareBodyGirl75

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Location
west jordan
First Name
Michelle
Truck Year
1975
Truck Model
gmc
Engine Size
5.7
These may help you start your di-ag. (Yes, I stole these like a thief in the night). A good test light and multimeter are essential. Sounds like you probably need to start from scratch. Also don’t forget to check power from the battery to the starters and to the alternator and finally from the starter to the fuse panel first since that is where power for the whole truck starts from. A lot of people chase gremlins because someone got creative powering the fuse panel “a better way.” Once you are 100% under the hood, then start under the dash.
Hey thanks. So I just got fed up with the nonsense of wires and the feeling that I know how my truck is and how she drives and when she is coming down sick or just simply needs a little bit of love, I had to get her fixed so I’m not having to deal with other people‘s mess so what I did was simply ordered a harness off-line, but I also ordered a new fuse panel, which is kind of nice just now that my wires are getting color-coded and they’re running along pretty smoothly. It’s taking me forever since I’m doing it by myself, but maybe this will actually fix a lot of her issues. Now there are questions I have with my new harness. It’s a 21 circuit and she is beautiful, but I haven’t mounted her in all the way yet I know I want to install some updated gauges, but I want to keep it still the old-school way as in that order that variety. I just haven’t decided on what I would like to do yet now I do have a fuel line wire and I have two fuel tanks. However, only one of them is running as the other one has a hole in it for the time being I’m not sure how I’m supposed to be running off my fuel line from the beach panel. I think I just got so worked up and so overwhelmed that I’m trying to figure out everything from scratch and so far just come along however it’s taking me this long just to get some of it done I appreciate everybody’s help. It means a lot to me more than words can say and that’s from the bottom of my heart so everybody been treating us I appreciate you 1 million and thanks for answering my question to get back to me and providing feedback and some answers and more you guys are amazing
 

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