Factory radio install

[bigboychevy]

Can't help with that, but there are wiring diagrams for all our trucks on the site somewhere. I would guess there would be powers and grounds for the cassette player and "head unit", some kind of communication wires as well. Let alone all the speaker wires , 2 to each speaker. So you probably will have to wire up the majority of them, depending on what you are trying to accomplish.

Thank you buddy you’ve been a massive help! Will try to find those wiring diagrams appreciate it!

 

[LTC_]

Thank you so much! Do you know if whatever plugs into this part of the CDM is the power plug? Mine has been cut, so I ordered a new plug, dreading having to wire it up because the plug has so many wires on it, not sure if they all need to be wired

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The 2 4 pin plugs are speaker outputs, separated by front-rear. The bottom left 6 pin plug is your power, ground, etc.

 

[df2x4]

Will try to find those wiring diagrams

If you haven't already, you might check the factory service manuals. You can download them here.

https://www.gmt400.com/threads/88-95-service-manuals.43575/

 

[AK49BWL]

Just gonna leave this here too.... https://www.gmt400.com/threads/88-94-factory-stereo-info.48716/

And this: https://www.ak49bwl.com/other/wires/1994K1500/Radio-AM-FM-Cassette.pdf

Each of the four connectors that enter the CDM on that side are keyed so you cannot insert any of them wrong. Personally I would go to a junkyard and snip off a stereo harness end from any 88-99 GMT400 - they're all compatible. Then it's a simple case of wire matching to what you have under your dash.

 

[bigboychevy]

If you haven't already, you might check the factory service manuals. You can download them here.

https://www.gmt400.com/threads/88-95-service-manuals.43575/

Thanks! That helped! What is confusing me is the guy who owned it before cut a lot of wires and I’m trying to figure out what those wires controlled. I have a few electrical issues and I feel it’s because of those cut wires. For example when I use the AC or heat there is a buzzing sound that comes in and out constantly; also the windshield wiper modes are all messed up, they don’t behave as they should and the wipers move erratically, in the brake lights the middle bulb only lights up, not the top or bottom bulb, no reverse lights or parking lights work. I know it’s a long list but it’s a project in progress lol

 

[bigboychevy]

Just gonna leave this here too.... https://www.gmt400.com/threads/88-94-factory-stereo-info.48716/

And this: https://www.ak49bwl.com/other/wires/1994K1500/Radio-AM-FM-Cassette.pdf

Each of the four connectors that enter the CDM on that side are keyed so you cannot insert any of them wrong. Personally I would go to a junkyard and snip off a stereo harness end from any 88-99 GMT400 - they're all compatible. Then it's a simple case of wire matching to what you have under your dash.

That’s probably what I’ll end up doing later this week. I also found a cassette with equalizer I’ll end up buying that too at the junkyard

 

[AK49BWL]

Thanks! That helped! What is confusing me is the guy who owned it before cut a lot of wires and I’m trying to figure out what those wires controlled. I have a few electrical issues and I feel it’s because of those cut wires. For example when I use the AC or heat there is a buzzing sound that comes in and out constantly; also the windshield wiper modes are all messed up, they don’t behave as they should and the wipers move erratically, in the brake lights the middle bulb only lights up, not the top or bottom bulb, no reverse lights or parking lights work. I know it’s a long list but it’s a project in progress lol

Buzzing is likely your recirc door motor, normal on startup and shutdown with most of these because the motor has broken gears internally. Or one of your other motors has broken gears. Wiper issues are usually the control board itself in the module on the firewall - just needs some touchup work on the solder connections and that'll probably be fine. The top bulb of the taillights is only for running lights, not brakes or blinkers. Reverse switch is at the bottom of the steering column, should be two or four wires going into a circular-looking module down there, check and see if those are there... Park lights may be a bad or dirty headlight switch, you can either replace or open it up carefully and clean it (this fixed my 93's lack of headlights control). And then there's also multiple fuses in the cab and fusible links on the firewall behind the battery to consider here for some of these things as well.

 

[Drunkcanuk]

All of the above, PLUS a lot of ground wires in these trucks that can cause headaches as well.

 

[bigboychevy]

Buzzing is likely your recirc door motor, normal on startup and shutdown with most of these because the motor has broken gears internally. Or one of your other motors has broken gears. Wiper issues are usually the control board itself in the module on the firewall - just needs some touchup work on the solder connections and that'll probably be fine. The top bulb of the taillights is only for running lights, not brakes or blinkers. Reverse switch is at the bottom of the steering column, should be two or four wires going into a circular-looking module down there, check and see if those are there... Park lights may be a bad or dirty headlight switch, you can either replace or open it up carefully and clean it (this fixed my 93's lack of headlights control). And then there's also multiple fuses in the cab and fusible links on the firewall behind the battery to consider here for some of these things as well.

I snapped some photos of the cut wires and the electrical setup in case you guys see something out of order.


I also made a video of the buzzing AC sound here it is:

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I can make a video of the electrical setup as well if you think that would help.

 

[AK49BWL]

Oh holy hell, that's your blower motor relays making THAT awful racket time for some new relays!!

The light blue/dark blue/brown/yellow wires are your rear speakers, the gray and tan wires are the left front, I'm not seeing the light and dark green right front speaker wires. CDM power is absent as well in those photos. Your photo of the convenience center looks about normal to me tho. No idea what that cut wire is to the screw, just that it's not factory lol