Mutt gauges?

[Sierra_Grande]

Hey all, new on here. I've had my '73 Burb for a really long time and finally decided to fix and upgrade the gauges. I have a really long story but will not put it all in this first post lol.

Really what got me going this weekend was just to replace the dash lights. I got some LED 194s that I like and figured I'd pop them in there. But of course the gauge backing plate was all crumbly... So I got onto LMC to order a new one. Then the questions came... They don't list one for a '73 with tach. I was just going to order the one for the '76-'77 but then started reading forums and got more worried about fitment... So next I pulled the whole cluster and disassembled it. Then I found something strange, a brake warning light buried under the speedo. All the gauges appear to be '73 but not sure what was done before I owned this. It appeared to me (by some mismatched screws) that someone had been in here before.

I was hoping for insight and opinions.

Posting some pics I took with the new lights and cluster assembled, and a couple disassembled. Thanks in advance

 

[Sierra_Grande]

Well it didn't let me post pics... I'll try again.

Do I have to pay to post pics or minimum post count or something? It doesn't say so here. I tried reading the instructions I promise lol

Thread 'Posting Pictures In A New Thread or A Reply' https://www.gmsquarebody.com/threads/posting-pictures-in-a-new-thread-or-a-reply.47726/

 

[Sierra_Grande]

Nevermind, pictures were too big lol. Here they are:

new bright bulbs

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On Bench:

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Brake warning light behind Speedo

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Lit up for fun:

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[idahovette]

1st pic NO oil pressure and 4500 RPM??? That's not good...........

 

[Sierra_Grande]

LOL good eye. It's not on.

I have a 6.5 swapped in. When the guy put it in he tried to connect the diesel tach wire to the gas tach and that's what I have now. One of the things I'm going to do is test the tach while I have it out.

 

[Sierra_Grande]

Winning! So a while back in preperation for this project I bought a Dakota Digital SGI-100BT. This little beauty is what I'm going to use to convert the diesel's W wire tach signal to the gas tach. What I didn't know was that it came with a test function! You get their app, connect everything up, and it will send a 2000 RPM signal. Awesome knowing I don't need to buy a tach. (reading 4500 RPM disconnected had me worried lol)

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Still deciding how I want to handle the hidden brake warning light...

 

[ali_c20]

Winning! So a while back in preperation for this project I bought a Dakota Digital SGI-100BT. This little beauty is what I'm going to use to convert the diesel's W wire tach signal to the gas tach. What I didn't know was that it came with a test function! You get their app, connect everything up, and it will send a 2000 RPM signal. Awesome knowing I don't need to buy a tach. (reading 4500 RPM disconnected had me worried lol)

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Still deciding how I want to handle the hidden brake warning light...

Use the foam as a template, drill 4 holes in the corners of the shape and cut it out with a dremel or something similar.
Refine the shape with needle point files and paint the edges black. That would be my approach.

 

[Sierra_Grande]

That's a good idea. I was thinking about that too. This has always been a resto-mod.

Based on the gauges they sell at LMC, my backing plate must be from a 76-80. They had a "tell tale" in the speedo. I don't think it's from the 80s, they seem to have more lights in the gauges, mine is only on the left.

What's weird is I don't see any of the gauges with tell-tales that exactly match the size of my warning indicator. That foam peeking out behind one of these gauges would not look nice... I'm wondering if there was another variation of the speedo with a smaller window.

1=73-75 2=76-69 3=79-80

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I'm also wondering if there's any scenario where my brake warnign light works anyway LOL. When I bought the truck it had already been converted to HEI. They must have worked on the gauges around then to make the tach work. Maybe they buried the brake light knowing it didn't work back then. It may not be thaty useful anyway. My parking brake is long gone and you can pretty much tell when the master cylinder fails

 

[hoagster]

I am going to ask you to do a favor for me? While your have it out can you take a picture of were all the screw clips are to mount the gage cluster to the dash. I have had mine out so long I can't remember there locations. Here's were I'm at putting things back together.

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[legopnuematic]

Your speedometer has been at some time replaced with a non tach speedo.

1973 tach cluster (photo from the net):

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On a non tach truck the brake warning lamp is where the fuel gauge is on a (non medium duty) tach cluster.

1973-1975 clusters used an ammeter, 1976+ used volt meters.

1976 speedometers added KM/H, tach speedos kept the single window for the brake light, non tach had no holes until 1977, 1978 the window widened for two indicator lamps.

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I don’t recall the exact year it was added, but my 79 does have a switch on the park brake for the brake light, my 76 does not. A 1973 the brake light should light up if the combination valve was to trip and the shuttle goes off center.

 

[hoagster]

Here's a picture of my 73 cluster. No tach and the bottom left small hole was were the brake light would have been but not wired for it. On a 73 if it had a large tach the fuel guage would be in that position. I put a check engine lamp in there for my LS swap.

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[idahovette]

I am going to ask you to do a favor for me? While your have it out can you take a picture of were all the screw clips are to mount the gage cluster to the dash. I have had mine out so long I can't remember there locations. Here's were I'm at putting things back together.

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Again........Damn that's a good looking dash!!!!!!!!

 

[hoagster]

Again........Damn that's a good looking dash!!!!!!!!

Yea need to get the front window in and bolt all that stuff down. So I can move on.

 

[Sierra_Grande]

I am going to ask you to do a favor for me? While your have it out can you take a picture of were all the screw clips are to mount the gage cluster to the dash. I have had mine out so long I can't remember there locations. Here's were I'm at putting things back together.

I will for sure grab you a pic. It will be Firday. I gotta work in Denver tomorrow and it will be a long day. I know some of them are the clips on the metal and some go into thebacking plate istself. Mine are cracked and stripped in the backing plate. I like your LS CEL

 

[Sierra_Grande]

Your speedometer has been at some time replaced with a non tach speedo.

1973 tach cluster (photo from the net):

On a non tach truck the brake warning lamp is where the fuel gauge is on a (non medium duty) tach cluster.

1973-1975 clusters used an ammeter, 1976+ used volt meters.

1976 speedometers added KM/H, tach speedos kept the single window for the brake light, non tach had no holes until 1977, 1978 the window widened for two indicator lamps.

I don’t recall the exact year it was added, but my 79 does have a switch on the park brake for the brake light, my 76 does not. A 1973 the brake light should light up if the combination valve was to trip and the shuttle goes off center.

Thank you Spencer! This was the exact info I was hoping to find! After disassembling, I knew something had to have been changed but never really dug into these clusters before.

Dang, I started looking on Ebay and found that gauge you grabbed a photo from. Dude wants $600 for it!

I went ahead and ordered a new backing plate from LMC for a '76 w/tach. I may be out hunting CL and Ebay for that speedo now that I know what I'm looking for. I'd love to have the right one

I also ordred a '76 volt meter. I've never seen the ammeter move in 24 years so assuming it's not working lol. I tested pin 3 and 4 on the cluster harness. There's no voltage on either one, ignition on or off. I read a few posts and it looks like people just get power for the volt meter off the temp gauge.