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**pjmoreland** · 02-04-2023, 03:46 AM

I found a 1991 tach gauge cluster at the wrecking yard that I'm going to put in my '89. I'm following the guidance in this thread:

http://67-72chevytrucks.com/vboard/s...d.php?t=313815

I opened up the gauge cluster this evening and swapped around the little fuses on the PCB to set my rear end gear ratio and tire size for the speedometer. I also disassembled the odometer and set it to match my current odometer.

My plan is to run the tach signal wire through the bulkhead connector on the firewall. I pulled a bulkhead connector from a truck at the wrecking yard this afternoon just to figure out how it's constructed and to harvest a set of contacts from it. Took me a while to figure out that there is a white plastic comb-shaped piece that locks the contacts into place. Everything is covered in black caulking. There was one empty slot in that connector, so hopefully it is the same way in my truck.

I also grabbed the gauge cluster connector out of the truck at the wrecking yard so I can use one of its pins for the tach signal. The truck that this tach gauge cluster came out of had the tach wire routed in a big bundle of wires through a firewall bulkhead pass-through (not a connector) on the passenger side. It then passed through a connector behind the glovebox, and then entered another bundle of wires that ran along the dash over to the gauge cluster.

02-04-2023, 03:46 AM	#842
pjmoreland Senior Member Join Date: Jan 2005 Location: CA Posts: 5,339	Re: What did you do to your truck today?? I found a 1991 tach gauge cluster at the wrecking yard that I'm going to put in my '89. I'm following the guidance in this thread: http://67-72chevytrucks.com/vboard/s...d.php?t=313815 I opened up the gauge cluster this evening and swapped around the little fuses on the PCB to set my rear end gear ratio and tire size for the speedometer. I also disassembled the odometer and set it to match my current odometer. My plan is to run the tach signal wire through the bulkhead connector on the firewall. I pulled a bulkhead connector from a truck at the wrecking yard this afternoon just to figure out how it's constructed and to harvest a set of contacts from it. Took me a while to figure out that there is a white plastic comb-shaped piece that locks the contacts into place. Everything is covered in black caulking. There was one empty slot in that connector, so hopefully it is the same way in my truck. I also grabbed the gauge cluster connector out of the truck at the wrecking yard so I can use one of its pins for the tach signal. The truck that this tach gauge cluster came out of had the tach wire routed in a big bundle of wires through a firewall bulkhead pass-through (not a connector) on the passenger side. It then passed through a connector behind the glovebox, and then entered another bundle of wires that ran along the dash over to the gauge cluster. Attached Images Last edited by pjmoreland; 02-04-2023 at 11:49 AM.