Gauge Swap Help And Wiring Diagram Needed

[wildmanaaron]

I just recenlty purchased a 1981 Blazer that had a non-gauge dash, but with two mechanical SUNPRO Temp & Oil Pressure gauges. This set-up was an ugly eyesore, so I went to the local junk yard and picked up a gauge dash out of a 1987 C/30, 350 TBI. I kept the pigtail off of the C/30 dash as well. Now I understand that I need to move the pins around on the end of the gauge harness that is currently on my Blazer, to match the printed circuit found on the back of 1987 model cluster. But this is where the story goes sour......

I have the Haynes manual for the 73-87 Chevy Trucks, but it does not have very clear or specific diagrams for what I need. I was wondering if someone had access to some better diagrams that would make it a lot easier for me to change all of this over?

Any help would be greatly appreciated!

I can accept emails at: wildmanaaron@hotmail.com

[79BIG10]

#1 Lt. green = high beam indicator lamp. #2 Gray = instrument lamps. #3 Black = ground. #4 Pink/black stripe = ignition. #5 Tan = oil pressure sending unit. #6 Pink/black stripe = ignition. #7 Pink = Fuel (will be spliced to #18 if you have dual tanks. Use the wire from #18 to hook up fuel gauge). #8 Black = ground. #9 Dk. green = water temp sending unit. #10 Black = ground. #11 Lt. blue = left turn signal indicator lamp. #12 Dk. blue = right turn signal indicator lamp. #14 Yellow = fasten seat belt light. #15 Md. blue = choke warning light. #16 Pink/black stripe = ignition. #17 Tan/white stripe (2) = park brake warning light. #18 Pink (2) = Fuel gauge sending unit (splice to other pink wire at #7).

[boxrodz]

Brandon - I have a little bit of a different configuration than what you posted, but it's close. I translated this from a '83 Helms shop manual. I also compared it to a late 89-91 Suburban Gauge Cluster.

Wildman - If you can get a Helm's Shop Manual, the manual will have the complete wiring schematics for the blazer. In the diagram below, some of the components use the same wiring colors, i.e. common ground wiring and also switch (ignition) power wiring.

[wildmanaaron]

Thanks. Hopefully this will help. This is the schematic for the 1981 model Dash right?

[boxrodz]

Unfortunately, I pulled the information out of a 83 C/K wiring schematic. I compared it to a 89-91 suburban gauge cluster. It's also close to what Brandon posted. So, I'm thinking it should be similar to what you have. (Although, 'close' doesn't cut it.) Maybe, someone with a '81 wiring diagram can confirm it.

[wildmanaaron]

Thanks for the help. Yes if anyone can submit a 1981 model diagram,I would greatly appreciate it as well.

[Slonaker]

See if this works...

Slonaker

[cliffsta]

Wow. Props 2 Slonaker to linking us (or at least me) to that... I'm gonna find that useful when I swap cabs and then motors in the next few months

(p.s. I tried to add to your reputation but apparently I love you too much and I gotta spread the love )

[wildmanaaron]

I found that somewhere else to. Most of the wires seem to match up for the same color from the harness that is in my 1981 Blazer to the dash that I bought out of the 1987 C/30.

However, I have run into a couple of differences that I want to ask about before I catch this Truck on fire hooking them up wrong.

1. The pigtail off of the 1987 cluster has three Ground wires, whereas the cluster harness in my 1981 Blazer only has two. Would it be okay, two splice two of the Ground wires from the new pigtail into one wire on the end of my harness in the Blazer?

2. The pigtail off of the 1987 cluster harness has three Pink/Black wires (#6/#4/#16) that I believe are for the Ignition, Volt, & Brake/Choke. However on my Blazer harness, all I have are two Pink/Black wires. I dont know which ones to splice into!

3. On the 87 model pigtail, I also have an extra Brown/White wire (#15) that I cannot figure out where it goes.

4. On my 1981 cluster, I have two Brown wires (#6 & #7) that I cant find where they go to

Anybody know??

[boxrodz]

Originally Posted by Slonaker

See if this works...

Slonaker

Yeah, I came across that same link on the Fullsize Chevy Forum. I've being comparing Autozone's wiring diagram to what is in the shop manual. I've noticed a few differences, but I'll have to look closer at it...

[boxrodz]

Originally Posted by wildmanaaron

I found that somewhere else to. Most of the wires seem to match up for the same color from the harness that is in my 1981 Blazer to the dash that I bought out of the 1987 C/30.

However, I have run into a couple of differences that I want to ask about before I catch this Truck on fire hooking them up wrong.

1. The pigtail off of the 1987 cluster has three Ground wires, whereas the cluster harness in my 1981 Blazer only has two. Would it be okay, two splice two of the Ground wires from the new pigtail into one wire on the end of my harness in the Blazer?

2. The pigtail off of the 1987 cluster harness has three Pink/Black wires (#6/#4/#16) that I believe are for the Ignition, Volt, & Brake/Choke. However on my Blazer harness, all I have are two Pink/Black wires. I dont know which ones to splice into!

3. On the 87 model pigtail, I also have an extra Brown/White wire (#15) that I cannot figure out where it goes.

4. On my 1981 cluster, I have two Brown wires (#6 & #7) that I cant find where they go to

Anybody know??

1. For safety reasons, I'd probably run another ground wire if the 87 cluster is requiring a ground wire for each of the three associated circuits.

2. Not sure. But, I only see two in the '87 wiring diagram coming from the fuse for the cluster. If three is required, then maybe run another wire from the fuse terminal to the connector. (Similar to reason in 1.)

3. Could it be from the brake switch (going to the brake light indicator on the cluster).

4. Could it be for the Choke light indicator.
Could the other be for the 4 wheel drive light indicator.

[wildmanaaron]

Once again, thanks so much for your help.

In regards to:

#3-The color is a dark brown with a thin white stripe, different than the two that seem to be ran to be for the park brake warning lights. So I still don't know where it is supposed to go I guess for sure or are you saying it is for the BRAKE light indicator on my dash?

#4-I'll have to check on this BROWN wire off of my 1981 Blazer. This Truck was a 2WD, so I didnt figure it would have wiring for the 4WD stuff??

[79BIG10]

Thanks for posting the link Slonaker. That's a great resource even from Auto Groan.

[wildmanaaron]

Well I got just about everything working now. Well sort of. The oil pressure gauge works fine, but we figured out the battery gauge is bad. I will replace that soon.

Also I may have to buy a new printed circuit or try putting some solder on the contact points, because my lights come and go randomly. Tonight the dash lights were working until I went to wash the Blazer. THen when I was trhough the wouldnt. Also earlier today the Temp gauge worked great. Now it reads way to high. When I wiggle the little metal clamps around it makes the needle go crazy. I just want to scream now. THose printed circuits are probably $75-$100!!

[jdmaffeo]

Since your old cluster was non gauge, did you replace the sensors on the engine to the gauge type? This could be your problem. When I did this I had to trace every single wire just to make sure that they went exactly where they were supposed to. I also found that some of the wires that were in the engine compartment terminated at the firewall and never hooked up in the cab to anything. Double check all of your wiring! It can be done!