4th small hole in late model clusters?

[Bennyt]

@Daveo91Burb

You must be registered for see images attach

Very cool! And that tach 0-7000 instead of 0-5000 like the truck tach. I did see that tach on GM Sports, but is was already listed as not available.

Aren't those in some other car as well?

I know GM crossed gauges into other platforms quite often. I've seen 62-65 Nova gauges in '70's and maybe even early '80's delivery vans.

 

[Turbo4whl]

Sounds like as good a theory as any I've come up with! I'm mostly just curious. I may try and put a another cluster light (that comes on with headlights) in one of those holes - The AutoMeter trans gauge has a dedicated light but it's so much brighter than the other gauges. If I left the bulb out and had a light in one of those holes I think it would shine through enough to illuminate the gauge.

When I put the AutoMeter boost gauge in the fourth hole I took it apart. Since it is a mechanical pressure/ vacuum gauge it was easy to mount in the plastic without it's case. The dial face was smaller than the hole, so I backed the face with a piece black plastic. That way it was lit up like the other gauges.

 

[Turbo4whl]

Aren't those in some other car as well?

I know GM crossed gauges into other platforms quite often. I've seen 62-65 Nova gauges in '70's and maybe even early '80's delivery vans.

I do not know.

@bucket May know.

 

[bucket]

There were step vans and motor homes that used various truck/van gauges, but I don't know of anything else that used the truck tach.

For several years, I had a fuel gauge from an '82-'85 S10 installed in my '79. The face wasn't the exact same size, but it fit in place with zero modification. If there was a tach option for those year S10's, it would fit too. But it would take modifications and the signal would need modified for a V8 too. At that point, might as well just install an '82-'89 Camaro tach from a V8 car. And if you get one from an earlier year, you can remove the built-in oil pressure guage and install the fuel gauge (from the same Camaro) in it's place. Then you get the same tach/fuel gauge setup.

 

[Rusty Nail]

Medium duty squares have a tachometer with a fuel gauge in the bottom. There would be a brake air gauge in the fourth small hole.

I installed this type tach in my '82 and put the turbo boost gauge in the fourth hole. In this picture you can see the tach with fuel gauge:

You must be registered for see images attach

If anyone is lucky enough to find this tachometer, you need to remove the fuel gauge resister from the back of your original fuel gauge and use it to replace the resister on the medium duty tach/ fuel gauge. Then the fuel gauge will be correct.

Pro Tip right there. Nice job.

 

[Rusty Nail]

There were step vans and motor homes that used various truck/van gauges, but I don't know of anything else that used the truck tach.

For several years, I had a fuel gauge from an '82-'85 S10 installed in my '79. The face wasn't the exact same size, but it fit in place with zero modification. If there was a tach option for those year S10's, it would fit too. But it would take modifications and the signal would need modified for a V8 too. At that point, might as well just install an '82-'89 Camaro tach from a V8 car. And if you get one from an earlier year, you can remove the built-in oil pressure guage and install the fuel gauge (from the same Camaro) in it's place. Then you get the same tach/fuel gauge setup.

I bet this works good, that's a great idea!
(and stupid simple to install )

Beware of GM parts interchangeability - it's WICKED!

 

[Raider L]

That brown wire and idiot light is the Alternator energize light. It comes on for a few moments after you start the engine and as soon as the alt. field wiring is energized it goes off. It's a very important light. If it doesn't come on, you field wiring in the alt. has a problem, probably the voltage regulator. If it comes on and doesn't go out there is a alt. problem. If it comes on, goes out as it should but then comes on intermittently then you have a alt. problem. Sorry I can't tell you the other two problems above but they are described in detail in the factory manual. They can be found on the internet.

 

[Daveo91Burb]

That brown wire and idiot light is the Alternator energize light. It comes on for a few moments after you start the engine and as soon as the alt. field wiring is energized it goes off. It's a very important light. If it doesn't come on, you field wiring in the alt. has a problem, probably the voltage regulator. If it comes on and doesn't go out there is a alt. problem. If it comes on, goes out as it should but then comes on intermittently then you have a alt. problem. Sorry I can't tell you the other two problems above but they are described in detail in the factory manual. They can be found on the internet.

Thanks, but do the late models with full gauge packages have that idiot light? Every example I've ever seen late 80s to '91 with gauges just have that hole blacked out. I already put my cluster back together so I can't check it out now, but I am curious if that brown wire would get energized after I start it as you say. Next time I have the cluster apart (hopefully long time from now) I'll check it out.

 

[Daveo91Burb]

Cluster all back together and everything works and looks good. I solved the over-bright trans temp gauge problem by simply putting in a less powerful LED. PO converted dash lights to LED but he left trans gauge with incandescent. My first attempt with LED replacement was way too bright, but found one much more suitable.

You must be registered for see images attach

 

[AuroraGirl]

Cluster all back together and everything works and looks good. I solved the over-bright trans temp gauge problem by simply putting in a less powerful LED. PO converted dash lights to LED but he left trans gauge with incandescent. My first attempt with LED replacement was way too bright, but found one much more suitable.

You must be registered for see images attach

ill accept donation of your tach that is in no way rare or expensive to procure outside of medium duty trucks, thanks!