Common dash cluster issues question

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FrozenCaveman

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Hi all,

I'm having the very common problem of my gas gauge not reading anything at all in my 71 Scamp. The temp gauge has slight movement to it with key on, but I don't think it's reading as accurately as it should. This was all working before I took my cluster out to have the speedo repaired, and following a 2-year hiatus because my steering box needed a rebuild (props to Straight Line Steering in San Jose), I'm finally trying to get everything working again.

I found that one of the bulb sockets has a broken tab, so I just swung by both NAPA and O'Reilly in town and neither had the socket in stock. While I'm waiting, I'm hoping someone can provide some tips on what the issue might be. I replaced the cluster voltage regular with a solid state model a few years back, so I hope it's not that. How does the cluster get ground? Could I have an issue with the screws connecting the cluster to the dash itself? Having just put the steering column back together, I'd rather not take it all apart again to remove the cluster. Can one bad socket cause this behavior?

Thanks for any guidance - frustrated that I don't have a replacement socket today. O'Reilly will have one tomorrow, NAPA not until Tue/Wed.

-John
 
................Let's see...............LOL

1....Cluster pc board harness connector pins. They can be repaired there is an OLD thread about this
2.....IVR connector contacts are sort of crimped into the board, and should be "soldered across" to the board traces
2....Gauge stud nuts are a joke. Replace them with "real" nuts and tighten/ loosen/ tighten them a few times to "scrub" the PC board contact area
3...Replace the IVR with a solid state replacement. A joint called RTE is one good one
4...Use a pencil eraser to clean / scrub the pc board where the lamp sockets make contact. Replace sockets as necessary, and "spread" / bend the contact fingers as needed for better contact. If you "go" LED bear in mind most of them are polarity sensitive, so if you get the LED/ socket in "wrongly" the LED won't light

There are hundreds of threads on here about testing gauge calibration. If you have a rheostat or old gas sender, you can use that for a resistor. If you have an oil (Ralley) cluster, all three gauges use the same resistances. Here is a photo someone doctored, of a gauge tester. The yellow print are the resistor values for empty, mid scale, and full scale

c-3826-jpg-jpg.jpg
 
Nice post, thanks. Mind you, not what I was hoping to hear, but sounds like if the socket doesn't fix the issue, I'll be pulling the dash back out. One of the dash mounting screw holes is (now?) broken, so I'm glad that the dash cluster itself isn't grounded to the frame of the car by way of the mounting screws.
 
FrozenCaveman said:
Nice post, thanks. Mind you, not what I was hoping to hear, but sounds like if the socket doesn't fix the issue, I'll be pulling the dash back out. One of the dash mounting screw holes is (now?) broken, so I'm glad that the dash cluster itself isn't grounded to the frame of the car by way of the mounting screws.
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?? I don't understand. Originally the cluster IS grounded (factory) by the mounting screws. The grounding pigtail I mentioned is a YOU install it deal
 
67Dart273 said:
?? I don't understand. Originally the cluster IS grounded (factory) by the mounting screws. The grounding pigtail I mentioned is a YOU install it deal
Click to expand...

Sorry, but I must be more blind than I thought - I read and re-read and I'm not seeing anything about a grounding pigtail in your post. Anyway, I do see the clips that must allow the lower 3 mounting points on the cluster to ground. The alternator speed nuts had been replaced previously with normal nuts, though I did notice that the ground side was finger tight.

That said, I think I found the problem. One of the pins got bent during my last install (I've been through this about 5 times). I'll have to dig up that article you mention about repairing them. It's hanging by about 1/3 of the material on one side, so if I stand it up, it stays in place until it gets some pressure on it. I swear, if it isn't one thing, it's another. I felt great about getting the steering box in there and getting the car back on the road, and getting the speedo repaired, and now I've broken part of the cluster. :/
 
Aw geez you are right I forgot to note that. Anyhow......add a grounding pigtail LOL
 
67Dart273 said:
Aw geez you are right I forgot to note that. Anyhow......add a grounding pigtail LOL
Click to expand...

LOL - anywhere in particular that you recommend connecting a grounding pigtail to the cluster? Pick one of the small hex screws holding the board to the cluster and put a small ring connector on it?

Is this the article you're referring to? Circuit Board Connector Pin Broke

The last poster, inertia, mentions in post #25 holding the pin to the board with a cotter pin to hold the old pin in place from the back, but still soldering it to the board. Since my pin is only partially broken (i.e. 2 of the 4 crimps to the board are likely severed), I can probably easily keep it in place while soldering. Thoughts on whether I can safely solder from the front of the board (i.e. trace side)? Redfish mentioned in post #18 the risk of pulling the trace off if the pin is only soldered. The caveat is that I'm not great with a soldering iron. Looks like fellow member MoparMike1974 services these boards, so worst case I can fall back to finding a local automotive electronic shop or sending it to Mike. Just itching to drive the car - argh.
 
The heavy wires on the amp gauge have always had ring terminals, real hex nuts, and internal toothed washers. All of the wires to gauges can be attached the same way. Dark blue to fuel, purple to temp', gray to oil. It aint so easy to bypass those pins for indicator lamps.
How I attach a addon ground wire... phillips head screw at lower center of center pod gets approx' 4 inches of wire with ring terminal. Then a male spade terminal other end. A length of wire with female spade terminal goes from there to behind the left kick panel. More or less mirror image the factories ground wire behind right kick panel. The spade terminals allow me to unplug my ground wire if necessary.
If/when I lower the column and pull the panel out a bit to trouble shoot in the car, I didn't loose my ground when I lowered the column.
 
Thanks for the tip on direct-connecting the gauges if needed. Do you have a recommendation on how to connect the wires without butchering the harness? I like the idea of a disconnect terminal for the pigtail to make it easier to remove the cluster. I see the phillips screw location you mention, and I'll take a look at the kick panel location. I've got the trace board sitting here next to me and I found a local radio shop that is willing to repair the pin for me - Sacramento Radio Expo. They've repaired the radios from a couple of my cars, including the Scamp. Very reasonable prices.

Since you mentioned it, what's the best practice for lowering the column to pull the cluster out? My steering box leaked at the input seal and I'm wondering if lowering the column several times to work on the cluster had an impact on it. Having just refurbished the box, I'd hate to damage a seal. For this job, I lowered the two nuts closest to the driver on the column as far as they would go without removing them entirely, and then the one nut near the firewall. I left the column to firewall nuts tightened. Just barely squeaked the cluster out over and to the left of the steering wheel. Previously, I think I fully removed the upper nuts to drop the column even more, but I think that may put a strain on the linkage to the upper steering box shaft.

-John
 
FrozenCaveman said:
Thanks for the tip on direct-connecting the gauges if needed. Do you have a recommendation on how to connect the wires without butchering the harness? I like the idea of a disconnect terminal for the pigtail to make it easier to remove the cluster. I see the phillips screw location you mention, and I'll take a look at the kick panel location. I've got the trace board sitting here next to me and I found a local radio shop that is willing to repair the pin for me - Sacramento Radio Expo. They've repaired the radios from a couple of my cars, including the Scamp. Very reasonable prices.

Since you mentioned it, what's the best practice for lowering the column to pull the cluster out? My steering box leaked at the input seal and I'm wondering if lowering the column several times to work on the cluster had an impact on it. Having just refurbished the box, I'd hate to damage a seal. For this job, I lowered the two nuts closest to the driver on the column as far as they would go without removing them entirely, and then the one nut near the firewall. I left the column to firewall nuts tightened. Just barely squeaked the cluster out over and to the left of the steering wheel. Previously, I think I fully removed the upper nuts to drop the column even more, but I think that may put a strain on the linkage to the upper steering box shaft.

-John
Click to expand...
On the typical day I wouldn't be back and respond before next morning. Have you ever got a revelation while under the shower? It just occurred to me that if I took my addon ground wire to the screw between heater core tubes where the factories ground wire is, I wouldn't need to remove a kick panel. I likely would need to move the glove box out of my path to that attach point. A little longer wire, tied to a blend door cable? Lots of different ways to do things. Butchering the harness would be necessary. the board contact pins are round, the female terminals are a bit oval shaped. Never was a lot of connection there. Somewhat surprising that the seize up. You would need to change to ring terminals some way if you route directly to gauges. 10-32 nuts and internal toothed washers are available at home depot, etc...
Some of the following doesn't apply to floor shift or manual trans...
I do remove the 3 bolts attaching column to firewall and that allows to column to drop further. scars in the plate show where it was mounted but column can change position lengthwise and a column shift neutral safety switch adjustment can change. Wont start in park :( A factory service manual shows how to set the column length so guts of box coupling are centered. And yes seal distortion can occur. It is possible to R&R that seal working under the hood. You'll need to drive out a split pin, use a pickle fork to get the box coupling off the shaft. Make a small punch mark and drill a small hole in the seals face. A drywall screw will go through, hit the land beneath the seal and draw it out. Please be forewarned... another member attempted this and didn't locate his hole and/or angle screw just right. Drill or screw damaged the perimeter of seal bore in his gearbox. New seal was good at the shaft but leaked at perimeter. I use a air powered offset drill with 1/4 inch chuck and 3/32 drill bit.
One more thing, that bolt on lower right side of upper column support goes into a caged nut. I crossed threaded that dang bolt once. Totally ruined my day. I wont ever carry my air ratchet under the dash again.
 
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What about the existing grounding pigtail from the steering column to the upper steering column mounting bolt? Wouldn't the mounting bolt be a suitable grounding location for the cluster as well?

Replacing the steering box was initially one of the worst jobs I've undertaken. Almost felt like pulling the engine was an easier task. But putting it back in was pretty basic, as was pulling the box the 2nd time, since it wasn't as nasty greasy or with frozen bolts. Can't remember if I had trouble pulling the upper seal. I know I mistook the thick washer outside the output seal as a seal itself and spent a while trying to drill through it before I realized my mistake. After putting it all back together, one of the internal paths/valves must have been plugged up, because I nearly took my hand off when I started the car, the wheel spun so violently to the left. Regardless of the metering block location, it just turned left and I had to pull the box again. Brought it to a professional that time. :/
 
yes there is a ground jumper on the steering column. If you remove bolts and lower the column to remove the inst' panel you will remove the ground. The panel wont work while dangling from its harness connectors if it isn't grounded. I like to test the panel before fully installing.
 
If you want to ditch some of the factory dash board connectors, I have bought the GM style connectors with pigtail wires. They are on Amazon in a variety of pin counts and are pretty cheap. If you have a soldering iron and some shrink sleeve you can really improve the 50 year old connections.
 
^^I assume you mean soldering pigtails to the board traces^^?? That is exactly what I ended up doing wth my 67 (I'm a cheap SOB) but at the time I used Molex style connectors from RadShack which of course is gone, but there are other sources of Molex / similar stuff.
 
67Dart273 said:
^^I assume you mean soldering pigtails to the board traces^^?? That is exactly what I ended up doing wth my 67 (I'm a cheap SOB) but at the time I used Molex style connectors from RadShack which of course is gone, but there are other sources of Molex / similar stuff.
Click to expand...

Yep, exactly! There is a pretty good variety of pre made connectors with wires available so you don’t need to assemble them like a molex. A little more work, but when you are done, it is for good. I see if I can find a picture.
 
I have a question, sort of related. But I think its this thread it is mentioned "having a good ground" to the instrument cluster. Is this is simple as running a wire from one of the screws in the metal cluster to a body ground somewhere? Where was the factory ground ran from on the cluster?
 
Looks to me, having a fairly original car that has been in my family since it was new, that the bottom 3 screws holding the cluster to the dash served that purpose. And from my experience, rather poorly. But yeah, I was going to take a pigtail from the lower center phillips/hex screw on the back of the cluster and run it to ground somewhere. I haven't decided yet, but maybe the steering column mounting bolt that already has a grounding pigtail for the column.

-John
 
The screws that attach board to housing are part of ground path. All of those screws and copper pads beneath them may need cleaning.
 
FWIW. This appeared to be the original ground wire on this rally cluster.
upload_2020-2-26_17-58-17-png.png

Other ring terminal attached the bottom lip of the metal dash at the radio support brace.
 
Dartswinger70 said:
I have a question, sort of related. But I think its this thread it is mentioned "having a good ground" to the instrument cluster. Is this is simple as running a wire from one of the screws in the metal cluster to a body ground somewhere? Where was the factory ground ran from on the cluster?
Click to expand...

Yes, and as mentioned the cluster was grounded with the mounting screws.
I have seen speedo cables burned from the cluster loosing its ground to the dash metal.
 
I think there are at least three screws on the circuit board that are used to ground circuits on the board. Clean those and put star washers on them to improve your grounds on the board.
 
Mike69cuda said:
I think there are at least three screws on the circuit board that are used to ground circuits on the board. Clean those and put star washers on them to improve your grounds on the board.
Click to expand...
There's the screws for lamp grounds.


upload_2021-5-20_11-0-32.png


And on the rally panel there's a ground contact on casting for the fuel gage/IVR.
upload_2021-5-20_11-9-53.png
upload_2021-5-20_11-11-17.png


IIRC the screws that mount the bottom of the instrument panel assembly to the dash provide an additional metal to metal ground path.
upload_2021-5-20_11-16-45.png
 
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