1973 Blazer - Tach Conversion

[Kyle K]

Hey folks, I've been racking my brain on this and hope you can help. Simply put, I want to put a tach in my dash, remove big fuel gauge, and replace ammeter with small fuel gauge. And I want to keep the brake warning light. And the mechanical oil gauge. I'm familiar and comfortable with re-pinning the cluster to fit the board, and moving gauges. Not into the fancy new electric gauge boards either.

So the situation...my current cluster backing plate can't accommodate this because the ammeter position (where i want small fuel gauge) only has two posts going to printed circuit, and fuel gauge needs three (sender, power, ground). I found one on LMC that seems to work with three posts. I know I'll need to drill a hole for tach wires to come through backing plate, in conjunction with tach bracket.

My problem...I'm good on gauges, and cluster backing plate. But I can't find a printed circuit for the life of me that will fit this. All of these only have two positions in that upper right (when looking at it from back), when I need three for fuel gauge. When I go up in years and find the correct one there, I lose the brake warning light.

So am I trying to make a combination that never existed at all and that's my problem? In OEM 1973 with tach, did clock replace brake warning light? I can't find any info on options anywhere. I've put a few pics below with my logic. Thanks for your help, ya'll always seem to come up with good info. Appreciate it!

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[Dave M]

I think your trying to make something that doesn't exist. Put the fuel gauge where the brake light was, and use a later speedometer face plate that incorporates the brake light. I have thought of fitting a tach' to my '76, but l too would rather have the fuel gauge in a more prominent position. Good luck with your project.

 

[Itali83]

Just run a separate wire directly to the fuel gauge that you need. Use the circuit board for two of the pins and your own separate wire for the third. I did this when I put a second temp sensor where the clock could go for a transmission temp gauge. If you’re good enough to do rest of this custom job, don’t let one wire stop you.

Ben

 

[Kyle K]

Hey folks, appreciate the feedback, and I've thought a little more about this and think I've figured out my direction. Here is my rational after thinking more...

• My goal is old-school functioning gauges, but don't necessarily need to be period-correct (I'm not in full restoration mode)
• Also, forgot to mention the PO put a Painless wiring harness in (which is nice). I don't know which version/model, but at quick glances on Painless's site, looks like they're not liking ammeters. And PO's work is very suspect, so I've been redoing a lot of his mistakes
• I can accomplish my "brake warning light", but by the light under the tach in that open window, and just wire it to there (thanks Dave M)
• Will use new free space on bottom left for my new small fuel gauge since new cluster/circuit will support it
• Will replace ammeter for new voltmeter gauge (1st gen style), still only needing two posts. (I'm scared to death of dealing with an ammeter due to fire issues, plus, I don't even think my Painless harness is setup to handle it). Read a lot of newer one-wire alternators don't like ammeters either. And a voltmeter seems more usage practical.
• So looks like I'll get one of those new clusters from LMC (prob 76 version so keep mechanical oil cut-out), along with printed circuit (mine on last legs) and gauges.

Two questions I have now....

• Assuming voltmeter is way easier hookup, and just basically power and ground, right? I'll look up wiring stuff later so don't want to derail here, but simply, it's just those two right?
• To still be alerted to brake issues by the brake warning light under my new tach (in the window), I'll wire to that bulb. But where do I find those red covers that show the issue? Been searching and either don't have right terms or I'm missing something (image below)
• I don't plan on using the other three bulbs (new speedometer is full with no window, so will cover those bulbs). And new tach with window...one bulb to show brake warning light....think I should wire the other bulb to anything else?

Where to find? LMC looks to only sell foam spacer, not indicator lens
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[Kyle K]

Update...found the lens on eBay under search of "gauge cluster warner light cover/screens/bezels". On the way. Will post some pics to let you know how it all turns out. Appreciate the input.