No gauge lights

[Hillbilly]

Got a new circuit board for my 81 still got no lights on cluster,bulbs good,sockets good,good ground (goes into ash tray housing)got running lights,head lights,brake,turn signals
Dome light comes on when turn switch
Old circuit board was peeling and lifted
Thought that was issue.Did notice a open slot on harness connector #14 no wire in that position.what y’all think?s


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[bucket]

Illumination fuse?

IIRC, the backlight power wire to the cluster is gray.

 

[Hillbilly]

Hey how many grounds should that cluster have ?mine is one of the bulb sockets with a round end that snaps into my ash tray holder.


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[78C10BigTen]

I had the same issue in my 78 and it turned out it was the actual headlight switch you pull out to turn on the head lights. Soon as i swapped it with a junk yard one they came right on.

 

[Charlie]

If you haven't tried it yet, unplug switch connector and re-connect. Could just be poor connection.

 

[Hillbilly]

Got a new switch for headlights still no cluster lights


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[chengny]

Hey how many grounds should that cluster have ?mine is one of the bulb sockets with a round end that snaps into my ash tray holder.


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Are you talking about this?:

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If so. that isn't a ground, it's a fiber optic cable. It diverts a bit of light from the lamp in the upper RH corner of the cluster and use it to illuminate the ashtray:

You must be registered for see images attach

Your cluster wiring has two connections to ground. While looking at the male plug (i.e. the harness side) with the larger locating tab on the bottom, the ground wire pins are:

With no gauges - the lowest one on the left and the 4th from the top on the right.

With gauges - lowest one on the right and 3rd from the top on the left.

Both of these ground pins are lead to a common splice point. That splice point has one lead which is connected to the ground bus block - located on the side wall above the e-brake actuating mechanism.

Is it just the cluster lighting that is out - or are the gauges (if you have gauges) out as well? If no gauges, do the warning lights/gas gauge work? If everything else is working, that would pretty much eliminate a ground issue because all the components on the PC board share the same two grounds.

Look at the hot side instead of the ground side;

The instrumentation lighting is fed from the H/L switch on the DK GRN 44 lead. The DK GRN 44 lead feeds the line (inlet) side of the INST LPS fuse. I am sure you've checked that fuse - and with a meter - right? The load side of the fuse is connected to the GRY 8 lead which goes directly to the cluster plug. It terminates at the 2nd pin from the top on the LH side (looking at the male plug) - that is with or without gauges.

You will have to use a meter - or test light - to trace the circuit and see where the power is being lost. Do these checks with the dimmer rheostat turned all the way up:

Pull the INST LPS fuse and check for power on the line side (should be the RH side looking fwd). If there is power there, that would confirm that the DK GRN 44 lead from the H/L switch is good and power is available to the fuse. If not, check the other end of the DK GRN - at the H/L switch and confirm power there. Power at the H/L switch and not at the fuse means a broken DK GRN lead.

If power is coming into the fuse, the next check is for power (on the pin connected to the GRY 8 lead) at the male side of the cluster harness connector.

That should get you started.

 

[Hillbilly]

Hey thanks for info,I’ll get on it in little bit when warms up some,so that is fiber optic man how bout that would have never known.
Yea ever who wired this truck made a mess under dash but what I paid for it
I’ll deal with it.Thanks to all u fellers with great info,


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[bucket]

Are you talking about this?:

You must be registered for see images attach

If so. that isn't a ground, it's a fiber optic cable. It diverts a bit of light from the lamp in the upper RH corner of the cluster and use it to illuminate the ashtray:

You must be registered for see images attach

Your cluster wiring has two connections to ground. While looking at the male plug (i.e. the harness side) with the larger locating tab on the bottom, the ground wire pins are:

With no gauges - the lowest one on the left and the 4th from the top on the right.

With gauges - lowest one on the right and 3rd from the top on the left.

Both of these ground pins are lead to a common splice point. That splice point has one lead which is connected to the ground bus block - located on the side wall above the e-brake actuating mechanism.

Is it just the cluster lighting that is out - or are the gauges (if you have gauges) out as well? If no gauges, do the warning lights/gas gauge work? If everything else is working, that would pretty much eliminate a ground issue because all the components on the PC board share the same two grounds.

Look at the hot side instead of the ground side;

The instrumentation lighting is fed from the H/L switch on the DK GRN 44 lead. The DK GRN 44 lead feeds the line (inlet) side of the INST LPS fuse. I am sure you've checked that fuse - and with a meter - right? The load side of the fuse is connected to the GRY 8 lead which goes directly to the cluster plug. It terminates at the 2nd pin from the top on the LH side (looking at the male plug) - that is with or without gauges.

You will have to use a meter - or test light - to trace the circuit and see where the power is being lost. Do these checks with the dimmer rheostat turned all the way up:

Pull the INST LPS fuse and check for power on the line side (should be the RH side looking fwd). If there is power there, that would confirm that the DK GRN 44 lead from the H/L switch is good and power is available to the fuse. If not, check the other end of the DK GRN - at the H/L switch and confirm power there. Power at the H/L switch and not at the fuse means a broken DK GRN lead.

If power is coming into the fuse, the next check is for power (on the pin connected to the GRY 8 lead) at the male side of the cluster harness connector.

That should get you started.

Now see, that's what I attempted to say in my post. But you said it WAY more informative and smarter like.

 

[Hillbilly]

Hey guys my gas gauge my volts gauge work I’m running mechanical on oil and temp till I can get my sending units for this’s 400sbc now right blinker stays on when pull out light switch go out when I actually set it on right turns
When light switch off it goes out blinkers work fine with no lights on ?


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[Hillbilly]

Still no cluster lights


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[bucket]

Still no cluster lights


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Did you test for power and ground as chengny described?

 

[Hillbilly]

Yes the volt and gas gauge are working.at the cluster.
My #8 wire is black not grey?


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[bucket]

Do you have any gray wires feeding the cluster? Did you check for power getting to the inst lmps fuse?

 

[Hillbilly]

Got power at instrument fuse yea there is a grey wire on cluster connector


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