gauge wiring

[bigd65]

First problem
OK, I thought I was going to have this thing nailed. I had all the wiring figured out. The green wire went to the temp sender,the blue wire to the oil sender the brown wire was still hooked to the alternator for the volt gauge and the tan wire to the fuel tank. The senders for the oil and temp are new, the fuel is still working ( I believe ) but the gauges for the temp, oil max out as soon as I turn the key on. The volt gauge still does not move.

I used a test light and have power from the temp gauge wire (bright light on the test light). The oil sender wire has power but the test light is dim. The volt gauge I dont know what to say, there is power going to it but the gauge does not move.

Second Problem
Then the POWER DISTRIBUTION BLOCK. I do not have the buss bar in between the two terminals, therefore I put an in-line fuse (10amp) and connected them with the fuse link. The red wire from the alternator is hooked to the small pin on the distribution block with the wire that goes back to the blower motor switch. The other wire, I think, powers the gauges (if Im correct) its hooked to the larger pin with the red wire that goes back to the wiring cluster on the fire wall.

Well the fuse blows when I mess with the two wire plug on the alternator. If I leave it, it dont blow the fuse. The fuse I am referring to is the fuse link I put between the two terminals on the Distribution block. I un plugged the alternator, the engine was not running, and when I plug it back in, it blows the fuse.

I have something wrong here that I thought I had all figured out and the only think I got done correctly was the plugs and wires. Truck runs great just no gauges.

[bigd65]

Ok I took the WHOLE cluster part, cleaned ALL the contact and hooked it back up. I have an oil gauge now but as soon as I hook up the temp sender wire to the sender, It maxed out. Im thinking the sender might be bad but its new.

The volt gauge, it still wont work. I have power to one side but not the top. and there is another terminal on the other side that does not hook to anything.

Fuel gauge is working

somebody on another page said something about a ground on the back of the cluster, where would this be. I dont have a ground coming off of the cluster.

My only othe question is concerning the junction block, still dont kow for sure that is correct

[hatzie]

It sounds like Your connector is pinned incorrectly for your cluster.

Originally Posted by bigd65

The green wire went to the temp sender

You have Dark Green from the Coolant-Temp sender. This is right.

Originally Posted by bigd65

The blue wire to the oil sender

According to GM... BLUE (there are 4 blue wires) feed one the indicator lamps.
TAN should be from the OIL pressure sender.

Originally Posted by bigd65

The tan wire to the fuel tank

According to GM... You have the oil pressure sender hooked to the FUEL gauge.
PINK is from the FUEL sender.

Wire Color Table compiled from the 73-87 wiring diagrams in our sister forum.

GM
CKT...DESCRIPTION.........WIRE COLOR
8......Cluster Lamps.........GRAY
11.....High Beam Lamp.....LIGHT BLUE
14.....Left Turn..............LIGHT BLUE
15.....Right Turn.............DARK BLUE
25.....Gen Telltale...........BROWN
30.....Fuel Gauge............PINK
31.....Oil Sender.............TAN
33.....Brake Lamp...........TAN/WHITE
35.....Temp Sender.........DK GRN
39.....Ignition Power.......PINK/BLACK
150...Grounds................BLACK
237...Seat Belt Warning...PINK/WHITE
931...Electric Choke........DARK BLUE
939...IGN Generator........ORANGE (idiot light clusters only)

[dropd80s]

^ This is correct, and as I mentioned in your other thread, the junction block on the fire wall is not fused between the two terminals. When you put a small fuse inline with the main power feed for the whole truck its gonna blow the fuse. Again like I reccommended in your other post, find or make a jumper for the two terminals, or tie them all to the same terminal, it doesn't matter.

[bigd65]

I dont have a tan wire for the oil sender just the blue, The diagram I have show two differnet dark blues, one for choke heater (i think) and one for oil pressure sender. Also when I ground the blue wire the oil pressure gauge pegs out. The oil pressure is now working , dosmy show very high pressure (about midway below 30 and when I rev it up, it goes almost to 30.

The temp (green ) it pegs when I hook it up to the temp sender. ( might be bad sender but is new )

Fuel gauge works.

Volt gauge still does not. I have power to one leg behind the gauge but still just does not move


Its very possible this cluster was changed because there has not been anything right on this truck yet.

Sorry about the Juction block, was just worried, seems like it should be fused

[hatzie]

Originally Posted by bigd65

Its very possible this cluster was changed because there has not been anything right on this truck yet.

Yes it has.

Originally Posted by bigd65

I don't have a tan wire for the oil sender just the blue, The diagram I have show two different dark blues, one for choke heater (i think) and one for oil pressure sender.

OK. Knowing what colors you're working with I'd guess you are finishing an incomplete conversion from Telltales (idiot lights) to gauges on a 81-87 truck. The Idiot lamp harness colors differ from the gauge harness colors and the idiot lamp plug is pinned completely different.

You need to verify each pin on your instrument panel plug. Verify every wire position against the tables below. Circuits 8, 11, and 30 are in the same position on both plugs everything else is suspect.

IDIOT LIGHT (TELLTALE) INSTRUMENT PLUG WIRE COLORS

CKT...DESCRIPTION.........WIRE COLOR
8......Cluster Lamps.........GRAY
11.....High Beam Lamp.....LIGHT GREEN
14.....Left Turn..............LIGHT BLUE
15.....Right Turn.............DARK BLUE
25.....ALT Field..............BROWN (not used on gauge panel)
30.....Fuel Gauge............TAN (PINK 77-80)
31.....Oil Sender.............DARK BLUE
33.....Brake Lamp...........TAN/WHITE
35.....Temp Sender.........DARK GREEN
39.....Ignition Power.......PINK (PINK/BLACK 77-80)
50.....IGN Generator........BROWN to Blower Switch(not used on gauge panel)
150...Grounds................BLACK
237...Seat Belt Warning...PINK/WHITE (YELLOW 77-80)
931...Electric Choke........DARK BLUE
939...IGN Generator........ORANGE to Blower Switch (not used on gauge panel)


1977-1987 GAUGE Plug Pinout by Circuit #s
150........35
14.........150
15..........30
237........39
-----......31
931........39
39..........150
33..........8
30..........11

73-87 IDIOT (Telltale) Panel Plug Pinout
14........150
15........33
39........25
-----....50/939
-----....39
150......35
237......31
----.....8
30.......11


TAN, LIGHT GREEN, and GRAY should orient the plug for you because they are not moving. You'll be missing a ground and ignition lead for the Volt Gauge.
Circuit 50/939 will probably sub for the missing circuit 39 ignition lead.

I'd stub off the brown wire from Circuit 25 @ 3" from the plug leaving enough of both pieces to connect them to additional wire.
At the plug solder on black wire long enough to reach a good ground this will give you the missing Circuit 150 for the plug.

The stub coming from the harness should be Circuit 25 from terminal L on the Delco SI alternator. You need to hook this to an ignition source with an inline resistor... Google "alternator resistance wire".

The Pinouts came from http://www.73-87chevytrucks.com/tech...rument_pg1.jpg. Id print the JPG I linked to and the wire-color circuit tables from this message.

Originally Posted by bigd65

The temp (green ) it pegs when I hook it up to the temp sender. ( might be bad sender but is new )

If this is still a problem with all the wires in the right slots of the panel plug check the resistance from the tang to the threads on the sender. If it's a dead short with the engine cold you probably have a glowplug inhibit sender.

Originally Posted by bigd65

Sorry about the Junction block, was just worried, seems like it should be fused.

It's the main power junction block. It's actually fused with a high amperage Fusible Link wire at the starter.

[bigd65]

This truck was peviously a Diesel and converted to gas. If that makes a difference

[bigd65]

This truck is really starting to get on my nerves. I am going to go out and check in a minute but I dont understand something. I have four wires coming out of the firewall for gauges: Tan, Blue, Green, Brown. I see on the diagram where it says tan used for gauges only on the oilsender but I see a Drk Blue for oil pressure switch also

Green I know is for Temp, It pegs when I hook it up Probably bad sender

Brown goes to the Alternater but I still cant get the Volt gauge to work

Tan I have hooked to the Fuel Gauge and it seems to work, it was hooked up there before and when I put gas in, It went up Besides there was one of the diagrams that showed the tan going to the fuel sender

The Dark Blue, I have it hooked to the oil sender, It seems ok, It reads a little low but goes up to almost 30 when I rev as do most GM have low pressure at idle. The blue shows to oil pressure on the same diagram you refer to but with about three other wires and then above that, it shows a tan wire going to the oil sender and say on gauge only clusters.

I m trying to follow what you had said about the pins, are you talking about the ones that go to the cluster

then there is the ground thing, Any pictures

[hatzie]

Originally Posted by bigd65

Ok I went and checked it out. The oil gauge wire ( Drk Blue) is hooked to the oil sender but wondering if this is correct. When I unplug the wire from the sender,the gauge pegs out. When I hooked it back up, it goes back to the normal reading. If thats correct in what it suppose to do, then I am getting closer. Green I know is for Temp, It pegs when I hook it up Probably bad sender

The Gauges should zero with the sender unplugged (Except the fuel gauge). You have the (BLACK & PINK) gauge voltage feeds reversed. This may be the issue with your TEMP gauge.

Originally Posted by bigd65

I don't understand something. I have four wires coming out of the firewall for gauges: Tan, Blue, Green, Brown.

Only 3 wires come from the firewall for the gauge senders... TAN #30, DARK BLUE #31, & DARK GREEN #35. It sounds like you have all three of them in the right positions in the panel plug.

Originally Posted by bigd65

I see on the diagram where it says tan used for gauges only on the oil sender but I see a Drk Blue for oil pressure switch also

That's where my initial confusion came from. Your wiring colors match the "Instrument Cluster W/O Gauges" but you have a gauge panel.

Originally Posted by bigd65

Tan I have hooked to the Fuel Gauge and it seems to work, it was hooked up there before and when I put gas in, It went up Besides there was one of the diagrams that showed the tan going to the fuel sender

Yup. This wire is in the right position in the plug because Circuit 30 is in the same position on both harnesses.

Originally Posted by bigd65

I'm trying to follow what you had said about the pins, are you talking about the ones that go to the cluster

Yes. The Pins I'm talking about are the ones that go to the cluster.

Your instrument panel plug should look like this.

Row A.............Row B
BLACK.............DARK GREEN [temp]
LIGHT BLUE......BLACK
DARK BLUE.......TAN [fuel gauge with tach cluster]
PINK/WHITE......PINK
----------........DARK BLUE [oil pressure]
DARK BLUE........[volt gauge ignition power] BROWN CKT#50??
PINK................[volt gauge ground]
TAN/WHITE.......GRAY*
TAN*[fuel]........LIGHT GREEN*

Originally Posted by bigd65

Brown goes to the Alternater but I still cant get the Volt gauge to work

You have found the BROWN Alternator wire Circuit #25. Circuit #25 is not for any gauge and should not be wired to a gauge cluster.

Let's try to help you get your volt gauge working.

There should be three BLACK grounds. The "Instrument Cluster W/O Gauges" harness only has two so you need to add one for the volt gauge.
There should be three PINK ignition power wires. Again the "Instrument Cluster W/O Gauges" harness only has two so you need to find or add one for the volt gauge.



One BROWN wire is from the alternator. This wire/pin is Circuit #25.
Stub the BROWN #25 wire off @ 3in from the plug leaving enough of both pieces to connect them to additional wire.
Connect a 3ft chunk of black 18ga wire to the plug stub. Route this wire to a chassis ground.
Connect a 3ft chunk of (not black) 18ga wire to the harness stub. Route this wire through a 470 ohm 1/2 watt resistor to an ignition power source.

The other BROWN wire in your plug goes to the heater fan plug and fuse panel. This wire/pin is Circuit #50 it should give ignition power to your volt gauge.

[bigd65]

Originally Posted by hatzie

The Gauges should zero with the sender unplugged (Except the fuel gauge). You have the (BLACK & PINK) gauge voltage feeds reversed. This may be the issue with your TEMP gauge.


Only 3 wires come from the firewall for the gauge senders... TAN #30, DARK BLUE #31, & DARK GREEN #35. It sounds like you have all three of them in the right positions in the panel plug.


That's where my initial confusion came from. Your wiring colors match the "Instrument Cluster W/O Gauges" but you have a gauge panel.


Yup. This wire is in the right position in the plug because Circuit 30 is in the same position on both harnesses.


Yes. The Pins I'm talking about are the ones that go to the cluster.

Your instrument panel plug should look like this.

BLACK.............DARK GREEN [temp]
LIGHT BLUE......BLACK
DARK BLUE.......------------
PINK/WHITE......PINK
----------........DARK BLUE [oil pressure]
DARK BLUE........[volt gauge ignition power] BROWN CKT#50??
PINK................[volt gauge ground]
TAN/WHITE.......GRAY*
TAN*[fuel]........LIGHT GREEN*





You have found the BROWN Alternator wire Circuit #25. Circuit #25 is not for any gauge and should not be wired to a gauge cluster.

Let's try to help you get your volt gauge working.

There should be three BLACK grounds. The "Instrument Cluster W/O Gauges" harness only has two so you need to add one for the volt gauge.
There should be three PINK ignition power wires. Again the "Instrument Cluster W/O Gauges" harness only has two so you need to find or add one for the volt gauge.



One BROWN wire is from the alternator. This wire/pin is Circuit #25.
Stub the BROWN #25 wire off @ 3in from the plug leaving enough of both pieces to connect them to additional wire.
Connect a 3ft chunk of black 18ga wire to the plug stub. Route this wire to a chassis ground.
Connect a 3ft chunk of (not black) 18ga wire to the harness stub. Route this wire through a 470 ohm 1/2 watt resistor to an ignition power source.

The other BROWN wire in your plug goes to the heater fan plug and fuse panel. This wire/pin is Circuit #50 it should give ignition power to your volt gauge.

I have power to one leg of the VOLT gauge. I checked it with the gauge installed but with the clear and black plastic covers off. Its on the right leg as the gauge is mounted inside cluster. There is one on the left side of the gauge that is not attached to anything, just a whole through the white plastic housing. the the top leg, I was figuring to be a ground pole

As far as the rest, I think the more I read it the more I am understanding it. Thanks a million for helping me, I may not be able to get back to it till this weekend, but again, thanks for helping me out

[hein97]

You have found the BROWN Alternator wire Circuit #25. Circuit #25 is not for any gauge and should not be wired to a gauge cluster.

Let's try to help you get your volt gauge working.

There should be three BLACK grounds. The "Instrument Cluster W/O Gauges" harness only has two so you need to add one for the volt gauge.
There should be three PINK ignition power wires. Again the "Instrument Cluster W/O Gauges" harness only has two so you need to find or add one for the volt gauge.



One BROWN wire is from the alternator. This wire/pin is Circuit #25.
Stub the BROWN #25 wire off @ 3in from the plug leaving enough of both pieces to connect them to additional wire.
Connect a 3ft chunk of black 18ga wire to the plug stub. Route this wire to a chassis ground.
Connect a 3ft chunk of (not black) 18ga wire to the harness stub. Route this wire through a 470 ohm 1/2 watt resistor to an ignition power source.

The other BROWN wire in your plug goes to the heater fan plug and fuse panel. This wire/pin is Circuit #50 it should give ignition power to your volt gauge.[/QUOTE]


i have pmd you Hatzie

[bigd65]

Ok I went and checked it out. The oil gauge wire ( Drk Blue) is hooked to the oil sender but wondering if this is correct. When I unplug the wire from the sender,the gauge pegs out. When I hooked it back up, it goes back to the normal reading. If thats correct in what it suppose to do, then I am getting closer. Still dont know about the volt gauge though

[maxx442]

This thread is from six years ago. Sure hope he has it sorted out by now.