Can you identify these wires/circuits?

[nab407]

Hey guys,

I've torn out all of the wiring in my truck, bought the shop manual, and am currently in the process of identifying, cleaning, rerouting, and looming all of my wiring. However, and as to be expected, I have run into some wiring that I cannot identify even with the shop manual diagrams. Please help!

My truck is a 1983 Chevy K10, 4x4, Auto, w/6.2L Diesel

1) Out of slot #18 on the instrument panel connector, exits two pink wires. One leads to nowhere (the one in question) and the other is circuit 30 and leads to the main firewall connector. Circuit 30 is labeled "Fuel Gauge to Tank Unit"***

2) Again, from the instrument panel connector, exits a pink wire from slot #7. It currently leads nowhere. I don't know what circuit it is.

3) From the seatbelt buzzer on the main fusebox exits a black and white wire. Goes nowhere. Circuit unknown.

4) Three wires that were jerry-rigged to go to my cigarette lighter by the previous owner. Two orange, one white. I traced them back to their source and found that one orange goes to the horn relay, the other orange goes to the headlight on/off switch, and the white goes to the headlight on/off switch, as well. Circuits unknown.

5) Black wire sourced to factory splice with one end going to seatbelt buzzer and the other going to ground. Circuit unknown.

6) Gray wire going to "Instrument" panel fuse on main fusebox with a 5-amp fuse. Circuit 8A in diagram, 'Fused No.44 Circuit' on circuit identification sheet.

7) Yellow wire traced back to 'Radio' 15-amp fuse on main fusebox. I'm pretty confident this is the radio power feed, but I just wanted to double check.

Any help would be GREATLY appreciated and I'll give everyone $1000!



*Disclaimer: I will not give anyone $1000.

 

[nab407]

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[nab407]

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[nab407]

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[nab407]

No one?

 

[Dadof2]

Bump for ya'.

 

[chengny]

1) Out of slot #18 on the instrument panel connector, exits two pink wires. One leads to nowhere (the one in question) and the other is circuit 30 and leads to the main firewall connector. Circuit 30 is labeled "Fuel Gauge to Tank Unit"***

Pink 30 (.8) is the tank level sensing leg. The schematics show a single lead running from the IP to the sender. What all that extra wiring is about is simply the method they devised to allow for installing the 3 different style of instrument panels (and the associated PC boards) and still use the same basic harness. The fuel gauge in the base IP - and the IP with gauges and with no tach - pins out at slot #18.

The fuel tank gauge on a deluxe IP (with gauges and a tach) pins out on #7.

So with the base and the no -tach IP's it is plug and play.

On the other hand - since the fuel gauge on a tach IP connects through #7 - the pink wire to the sender is in the wrong slot. Easy enough to fix; run a jumper over to the 7 pin and use slot 18 as a place to create the splice (the 18 slot on a tach type IP is not used - it's just an empty bay)

Your fuel gauge sender wiring is electrically fine - it just looks a little sloppy.

2) Again, from the instrument panel connector, exits a pink wire from slot #7. It currently leads nowhere. I don't know what circuit it is.

As explained above - that pink wire doesn't go anywhere or do anything - unless you have an IP with a factory tach.



3) From the seatbelt buzzer on the main fusebox exits a black and white wire. Goes nowhere. Circuit unknown.

That black/white lead is supposed to be connected to a switch located inside the belt retractor. That is how they decided to activate the seat belt warning lamp/buzzer. If the belt was left coiled up within the retractor, the switch would remain closed and the alarms powered. If you pulled the belt out and strapped yourself in, the switch would open and the alarms were preemptively disabled.

4) Three wires that were jerry-rigged to go to my cigarette lighter by the previous owner. Two orange, one white. I traced them back to their source and found that one orange goes to the horn relay, the other orange goes to the headlight on/off switch, and the white goes to the headlight on/off switch, as well. Circuits unknown.

Only one wire to the lighter (orange) the body of the lighter creates the ground. It dead ends there.

The white wire is the ground circuit for all interior lighting. The section that was connected to the cigarette lighter is supposed to be connected to the courtesy lamp under the dash.

The other end is lead over to the H/L switch (along with the white wire from dome light to which it is spliced). The power to the dome light is supplied on the orange wire as well.

The body of the H/L switch is grounded to the dash. When the dimmer is twisted all the way, it closes an internal switch to the steel dash. A ground leg is then created and the courtesy/dome lights illuminate. The white wire is also connected to the door jamb switches and will be grounded when the doors are opened.


5) Black wire sourced to factory splice with one end going to seatbelt buzzer and the other going to ground. Circuit unknown.

Two black ground leads are connected to the convenience center:

One of them is the ground for the shared warning buzzer (H/L's left on, key in the ignition, seat belt retracted). It is the larger of the two.

The other is the dedicated ground for the horn relay.

6) Gray wire going to "Instrument" panel fuse on main fusebox with a 5-amp fuse. Circuit 8A in diagram, 'Fused No.44 Circuit' on circuit identification sheet.

The gray wire is is the rheostat controlled (H/L dimmer) power to the 5 lamps within the instrumentation panel. That rheostat also provides power for the back lighting of the factory radio/ HVAC control panel - via the gray 8 circuit. A branch is also lead up the the convenience center to provide the "Lights are on" signal to the aforementioned buzzer.

7) Yellow wire traced back to 'Radio' 15-amp fuse on main fusebox. I'm pretty confident this is the radio power feed, but I just wanted to double check.

You got it Jackson.

Be aware however that these trucks do not have an unswitched power supply from the battery. The radio only can be (normally) powered up with the key in RUN/ACC positions.

If you want to install a newer style head unit (with a clock, programmable stations, etc), you will need to supply an additional power supply that is always hot.

 

[chengny]

Something else that might be important;

I noticed that the fuse block shown above is not stock to your truck. It's a C/K fuse block. But it's older, the last year that configuration was used was in 1984.

I mean, it's not a huge deal but it may one of the reasons you are struggling with wire/circuit ID:

I've torn out all of the wiring in my truck, bought the shop manual, and am currently in the process of identifying, cleaning, rerouting, and looming all of my wiring. However, and as to be expected, I have run into some wiring that I cannot identify even with the shop manual diagrams. Please help!

 

[nab407]

1) Out of slot #18 on the instrument panel connector, exits two pink wires. One leads to nowhere (the one in question) and the other is circuit 30 and leads to the main firewall connector. Circuit 30 is labeled "Fuel Gauge to Tank Unit"***

Pink 30 (.8) is the tank level sensing leg. The schematics show a single lead running from the IP to the sender. What all that extra wiring is about is simply the method they devised to allow for installing the 3 different style of instrument panels (and the associated PC boards) and still use the same basic harness. The fuel gauge in the base IP - and the IP with gauges and with no tach - pins out at slot #18.

The fuel tank gauge on a deluxe IP (with gauges and a tach) pins out on #7.

So with the base and the no -tach IP's it is plug and play.

On the other hand - since the fuel gauge on a tach IP connects through #7 - the pink wire to the sender is in the wrong slot. Easy enough to fix; run a jumper over to the 7 pin and use slot 18 as a place to create the splice (the 18 slot on a tach type IP is not used - it's just an empty bay)

Your fuel gauge sender wiring is electrically fine - it just looks a little sloppy.

2) Again, from the instrument panel connector, exits a pink wire from slot #7. It currently leads nowhere. I don't know what circuit it is.

As explained above - that pink wire doesn't go anywhere or do anything - unless you have an IP with a factory tach.



3) From the seatbelt buzzer on the main fusebox exits a black and white wire. Goes nowhere. Circuit unknown.

That black/white lead is supposed to be connected to a switch located inside the belt retractor. That is how they decided to activate the seat belt warning lamp/buzzer. If the belt was left coiled up within the retractor, the switch would remain closed and the alarms powered. If you pulled the belt out and strapped yourself in, the switch would open and the alarms were preemptively disabled.

4) Three wires that were jerry-rigged to go to my cigarette lighter by the previous owner. Two orange, one white. I traced them back to their source and found that one orange goes to the horn relay, the other orange goes to the headlight on/off switch, and the white goes to the headlight on/off switch, as well. Circuits unknown.

Only one wire to the lighter (orange) the body of the lighter creates the ground. It dead ends there.

The white wire is the ground circuit for all interior lighting. The section that was connected to the cigarette lighter is supposed to be connected to the courtesy lamp under the dash.

The other end is lead over to the H/L switch (along with the white wire from dome light to which it is spliced). The power to the dome light is supplied on the orange wire as well.

The body of the H/L switch is grounded to the dash. When the dimmer is twisted all the way, it closes an internal switch to the steel dash. A ground leg is then created and the courtesy/dome lights illuminate. The white wire is also connected to the door jamb switches and will be grounded when the doors are opened.


5) Black wire sourced to factory splice with one end going to seatbelt buzzer and the other going to ground. Circuit unknown.

Two black ground leads are connected to the convenience center:

One of them is the ground for the shared warning buzzer (H/L's left on, key in the ignition, seat belt retracted). It is the larger of the two.

The other is the dedicated ground for the horn relay.

6) Gray wire going to "Instrument" panel fuse on main fusebox with a 5-amp fuse. Circuit 8A in diagram, 'Fused No.44 Circuit' on circuit identification sheet.

The gray wire is is the rheostat controlled (H/L dimmer) power to the 5 lamps within the instrumentation panel. That rheostat also provides power for the back lighting of the factory radio/ HVAC control panel - via the gray 8 circuit. A branch is also lead up the the convenience center to provide the "Lights are on" signal to the aforementioned buzzer.

7) Yellow wire traced back to 'Radio' 15-amp fuse on main fusebox. I'm pretty confident this is the radio power feed, but I just wanted to double check.

You got it Jackson.

Be aware however that these trucks do not have an unswitched power supply from the battery. The radio only can be (normally) powered up with the key in RUN/ACC positions.

If you want to install a newer style head unit (with a clock, programmable stations, etc), you will need to supply an additional power supply that is always hot.

First of all, thank you so much for you help! I've got things a little bit better now. Here's the update:

1) I have the deluxe IP, so although I do not have a tach, I do have the clock and all the other 'bells and whistles.' I ended up splicing the two pink wires together which essentially creates the 'jumper' wire you mentioned.

2) Same.

3) I've left this alone and labeled until I get to the point of the resto where I'm installing my seat retractors back in.

4) According to my wiring diagram, the orange wire from the horn relay is the power for the cigarette lighter...weird.

5) Easy enough.

6) Still not sure about this one...where should I connect it?

7) Confirmed as radio power feed.

Something else that might be important;

I noticed that the fuse block shown above is not stock to your truck. It's a C/K fuse block. But it's older, the last year that configuration was used was in 1984.

I mean, it's not a huge deal but it may one of the reasons you are struggling with wire/circuit ID:

I've torn out all of the wiring in my truck, bought the shop manual, and am currently in the process of identifying, cleaning, rerouting, and looming all of my wiring. However, and as to be expected, I have run into some wiring that I cannot identify even with the shop manual diagrams. Please help!

Well, technically it is the correct fuseblock for the truck. You see, the entire wiring harness and 'convenience options (radio, A/C, etc.)' are from a 1983 K10. I have installed this harness (along with the crucial A/C) into a 1986 M1008 CUCV 1 1/4 ton pickup.

Thanks again for the knowledge!

 

[chengny]

4) According to my wiring diagram, the orange wire from the horn relay is the power for the cigarette lighter...weird.

Weird maybe, but that's how all these trucks are wired. The cigarette lighter was on the vital orange wire circuit (included in the HORN/DOME sub-circuit). That group of the fuse block is unswitched and hot at all times from the battery. The orange wire comes out of the fuse block and supplies power to the horn relay. At some point in the run from the fuse to the relay, it is branched off - and that leg goes over to the lighter.

Maybe it was considered "vital" to be able to light your smoke even if you didn't have the keys.

6) Still not sure about this one...where should I connect it?

The gray wire comes out of the fuse block in the lower left hand corner - at the INST LPS fuse. That is where the circuit originates. It is hard to tell from your pictures where the gray wire has been cut (and there may be some splices involved).

It feeds the backlighting for the instrument panel lamps, HVAC, radio and - in the case of an 83 - it also goes to the lamp in the wiper switch.

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[nab407]

4) According to my wiring diagram, the orange wire from the horn relay is the power for the cigarette lighter...weird.

Weird maybe, but that's how all these trucks are wired. The cigarette lighter was on the vital orange wire circuit (included in the HORN/DOME sub-circuit). That group of the fuse block is unswitched and hot at all times from the battery. The orange wire comes out of the fuse block and supplies power to the horn relay. At some point in the run from the fuse to the relay, it is branched off - and that leg goes over to the lighter.

Maybe it was considered "vital" to be able to light your smoke even if you didn't have the keys.

6) Still not sure about this one...where should I connect it?

The gray wire comes out of the fuse block in the lower left hand corner - at the INST LPS fuse. That is where the circuit originates. It is hard to tell from your pictures where the gray wire has been cut (and there may be some splices involved).

It feeds the backlighting for the instrument panel lamps, HVAC, radio and - in the case of an 83 - it also goes to the lamp in the wiper switch.

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Thanks again, you are full of helpful knowledge. For the 6) Gray Wire, it is not connected to anything at all so it simply comes from the fuse box and then it is cut. Do I need to splice it into something or what should I do with it?

Also, my diagram shows the cigarette lighter orange wire feed 'coming from' the horn relay, not going to it...

 

[chengny]

For the 6) Gray Wire, it is not connected to anything at all so it simply comes from the fuse box and then it is cut. Do I need to splice it into something or what should I do with it?

You are going to have to do some hunting around for the other side of the cut on the gray lead. It is not a huge circuit. After exiting the fuse block, it only splits off to 3 places instrument cluster, HVAC control panel, radio power connector. Your gray circuit may also feed the wiper switch.

A good place to start tracing the wiring back (to find the point where it was cut) is at the IP harness plug. If only because it is the closest to the fuse block. Holding the IP harness plug in your hand (with the plug-in side facing you and the smaller locating notch on the bottom) the gray wire will come in on the right hand side, second slot from the bottom:

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Start there and trace back to the point where the feed from the fuse block was cut.


Also, my diagram shows the cigarette lighter orange wire feed 'coming from' the horn relay, not going to it...

That's what I was saying too - it's just a matter of semantics. It goes without saying that - since the lighter is the "home run" (i.e. last component on the run of the circuit) - the power must feed into it and not from it.

 

[nab407]

For the 6) Gray Wire, it is not connected to anything at all so it simply comes from the fuse box and then it is cut. Do I need to splice it into something or what should I do with it?

You are going to have to do some hunting around for the other side of the cut on the gray lead. It is not a huge circuit. After exiting the fuse block, it only splits off to 3 places instrument cluster, HVAC control panel, radio power connector. Your gray circuit may also feed the wiper switch.

A good place to start tracing the wiring back (to find the point where it was cut) is at the IP harness plug. If only because it is the closest to the fuse block. Holding the IP harness plug in your hand (with the plug-in side facing you and the smaller locating notch on the bottom) the gray wire will come in on the right hand side, second slot from the bottom:

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Start there and trace back to the point where the feed from the fuse block was cut.


Also, my diagram shows the cigarette lighter orange wire feed 'coming from' the horn relay, not going to it...

That's what I was saying too - it's just a matter of semantics. It goes without saying that - since the lighter is the "home run" (i.e. last component on the run of the circuit) - the power must feed into it and not from it.

I see... Well I'll do some searching tonight when I get home. I know that the part coming from the IP connector does lead into a splice. I don't have any radio wiring or a connector for it (has been cut out), so I'll have to check for the wiper switch and HVAC controls. I'll let you know what I find so we can hopefully get this figured out!