Help with malfunctioning cluster.

[Dano500]

I’m wanting to get started on putting new dash pad in, but I know it will be easier to deal with this now. I’ve searched other threads and have found some info, but would appreciate some help piecing together necessary steps.

So, only the volt meter works in the gauge cluster. It doesn’t light up with headlights, so I switched out the headlight switch and no change. There is a gauge cluster at the bottom of dash for oil, temp and volts, so I know they had to have disconnected original wires that corresponded to cluster, but I can’t find any loose wires in engine bay. The temp is a darker green and the oil sender wire is tan, right?
Assuming I were to find them and get them reconnected, I still have problem of no lights in cluster. So, I read in a thread that when fuel, oil & temp aren’t working in cluster to check the grounding of the cluster, so my question here is where are the grounding connections?

On top of that, I have a loose connector- yellow and purple wires from steering column that I cannot find a plug for it. Maybe this is the problem?

With regard to all of this, the only thing I have done is a new fuel sending unit.

I want to get cluster working, instead of using the pod below. I’ve attached pics of what I think you all could find useful in helping me out, and I really appreciate you for taking time out to help me.

-Dan

 

[Dano500]

Here is the circuit board. I don’t know anything about this, but I didn’t see anything that looked burned. The second pic is the purple/ yellow connector that I can’t find what it goes to. And of course I have no idea where to plug connector in third pic.

 

[Randy and Easton]

Dan, the third picture shows the grounds which are attached to the bracket for the parking brake. The cluster ground there. Clean all the grounds, that is a great start. Our truck is a ‘76 so we can’t help any further but what we have learned in the build on these trucks if there is ever an electrical issue always start with grounds.

Did you have picture of purple wire from the column you spoke about? Purple on our column is for neutral safety switch.

Randy and E

 

[plugugly]

pull the plug off your dash bezel. There are (at least on my 87) three black wires in that plug. Check for continuity to ground to see if they are working. I believe the number 5 is ground for sure, and then the bottom lead on that side is water temp.

hate to ask the obvious but the bulbs and fuse are good?

this is the diagram I have been using as I look into my dash. Think I found it here on this site

 

[Dano500]

Dan, the third picture shows the grounds which are attached to the bracket for the parking brake. The cluster ground there. Clean all the grounds, that is a great start. Our truck is a ‘76 so we can’t help any further but what we have learned in the build on these trucks if there is ever an electrical issue always start with grounds.

Did you have picture of purple wire from the column you spoke about? Purple on our column is for neutral safety switch.

Randy and E

They do look fairly rusty. I’ll clean them for sure. Thank you. The purple and yellow connector is in the second post and the second pic. The site wouldn’t let me post all eight pics with initial post.

pull the plug off your dash bezel. There are (at least on my 87) three black wires in that plug. Check for continuity to ground to see if they are working. I believe the number 5 is ground for sure, and then the bottom lead on that side is water temp.

hate to ask the obvious but the bulbs and fuse are good?

this is the diagram I have been using as I look into my dash. Think I found it here on this site

Thanks for the help. So the fuse is good. I pulled all the bulbs and found one burned one.

Sorry for the dumb question, but how do I check continuity? Touch ground circuit with one pole if mm and what else?

I’m taking it all apart right now. I thought I would figure out how to check each gauge as well.

 

[RanchWelder]

There's a plastic sheet across the back of the cluster with copper flat strips in a maze back there.
In order to expose and remove the cluster, you could easily break the speedometer needle or not put it back on correctly, so it is calibrated again.

Be prepared to make a mistake or two, if you tear it down.
The high quality Dakota is $$$$.
Not much else actually reads the speed sensor off the transmission very accurately. They have the secret sauce and they charge for it accordingly.

Let's hope sanding and polishing that ground mounting point will get you up and running without damages to the cluster or the special plastic flat wiring system GM employed behind your cluster. If it cracks or the lighting plugs are missing or the circuitry is bad or corroded from water egress, you'll be looking for a replacement cluster and possibly a new speed sensor.

Whatever you do, make certain you have a plan before you pull that orange needle off the pin on your speedometer.

 

[Dano500]

I swear, sometimes I want to take this thing to the trash compactor and smash it into a little box. Lol

I don’t know what the heck the P.O. was doing. It seems like so many connections on this thing are disconnected. I don’t even know how it runs.

I traced the green temp gauge wire and it goes with the bundle of wires to the back of the motor and then I lose it behind distributor. I found a black wire that is loose and not connected to anything- single pin. It also goes to back of motor. The pink and yellow wires from valve cover aren’t connected and it seems like there is the oil gauge sender at back or distributor, but another one by filter.

This truck is so frustrating. Lol

 

[plugugly]

Sorry for the dumb question, but how do I check continuity? Touch ground circuit with one pole if mm and what else?

I’m taking it all apart right now. I thought I would figure out how to check each gauge as well.

get a volt meter and select the continuity. put one probe at connector and then the other to the other end of the wire where it would attach to the sender of your choice. You may need to make a jumper wire that will be long enough for the voltmeter probes to reach. I would think an internet search on how to check continuity would help. The other option is to use it as an ohmeter and check ohms just right there at the gauge. Probe the black ground and one of the sender wires (green for water temp, oil is tan i think) You should get some level of ohmeter. the ohmeter selction on the voltmeter needs to be fairly big. My smallest setting was 200 and it kept showing fault until I selected like 20 thousand or something.
I barely understand this, but just played with it all the last few weeks.

 

[Dano500]

@plugugly I figured it out and took out all three gauges and checked them and they are functional. I reinstalled them and checked their corresponding ground and power on the circuit board and the board is good.
The problem I’m having now is I traced the green wire and it isn’t cut, and it goes back behind motor somewhere. I don’t understand.

 

[mtbadbob]

I swear, sometimes I want to take this thing to the trash compactor and smash it into a little box. Lol

I don’t know what the heck the P.O. was doing. It seems like so many connections on this thing are disconnected. I don’t even know how it runs.

I traced the green temp gauge wire and it goes with the bundle of wires to the back of the motor and then I lose it behind distributor. I found a black wire that is loose and not connected to anything- single pin. It also goes to back of motor. The pink and yellow wires from valve cover aren’t connected and it seems like there is the oil gauge sender at back or distributor, but another one by filter.

This truck is so frustrating. Lol

The sensor by the distributor is a "pressure sensor", the one by the filter is sending unit for the gauge.

 

[mtbadbob]

There's a plastic sheet across the back of the cluster with copper flat strips in a maze back there.
In order to expose and remove the cluster, you could easily break the speedometer needle or not put it back on correctly, so it is calibrated again.

Be prepared to make a mistake or two, if you tear it down.
The high quality Dakota is $$$$.
Not much else actually reads the speed sensor off the transmission very accurately. They have the secret sauce and they charge for it accordingly.

Let's hope sanding and polishing that ground mounting point will get you up and running without damages to the cluster or the special plastic flat wiring system GM employed behind your cluster. If it cracks or the lighting plugs are missing or the circuitry is bad or corroded from water egress, you'll be looking for a replacement cluster and possibly a new speed sensor.

Whatever you do, make certain you have a plan before you pull that orange needle off the pin on your speedometer.

Why would you pull off the speedo needle to get at the circuit board??

 

[RanchWelder]

On the 87' cluster, there are 2 screws to remove the black metal plate over the green plastic cluster housing.
In order to verify the gauges are actually contacting correctly and the light bulbs are inserted or working, you have to pull the needle to expose the inside of the cluster. It's not hard to do, just getting it back on accurately can be a pain.
Old plastic breaks easy. Mine went back on 10mph wrong and messing with it broake it.
I'm running a Sport Comp Speedometer and using the odometer for fuel ups for now, until spring when I can rewire my fuel gauge.

My dash wash all broken plastic parts. Dakota is too much money with my transmission being modified.

 

[Dano500]

The sensor by the distributor is a "pressure sensor", the one by the filter is sending unit for the gauge.

Do all the trucks have both? I thought it was a one or the other thing. Once I find the tan wire, that corresponds to the cage in the cluster, I plug it to the sending unit by the filter, right?

 

[AuroraGirl]

Do all the trucks have both? I thought it was a one or the other thing. Once I find the tan wire, that corresponds to the cage in the cluster, I plug it to the sending unit by the filter, right?

electric choke is near the filter. If you have a gauge and electric choke you would have both

 

[mtbadbob]

Do all the trucks have both? I thought it was a one or the other thing. Once I find the tan wire, that corresponds to the cage in the cluster, I plug it to the sending unit by the filter, right?

I'm not sure about the 84 models, but I believe the sending unit wire on my '87 is a medium brown color, so I guess you could call it tan. It should have a single spade terminal in a plastic clip about 1" long and it comes around the back of the engine and drops down behind the exhaust manifold.