dash wiring hassel

Raider L

Full Access Member
Joined
Sep 1, 2020
Posts
1,757
Reaction score
821
Location
Shreveport, LA
First Name
William
Truck Year
1974
Truck Model
C10
Engine Size
355
Well, I've put it off long enough so today I pulled the truck up in front of the carport so I'd have all the comforts of home while I was dealing with the little wiring task I had in my truck

And it was rewiring all the lights in my Autometer gauges. Why did I have to do that? Because when I was rebuilding my truck I had the entire dash apart and did the wiring in layers. Boy did it look good when I was done. And as long as I've worked on aircraft you'd think I would have known to build in extra length to every wire in anticipation of having to pull the instrument panel at least one of these days. But noooo!
After struggling with trying to get the instrument panel out far enough to get my big hands behind it just to change a dang bulb, I finally psyched myself up enough today to get it done.

The idea I had many years ago when I rebuilt the instrument panel was putting all the gauge bulb grounds into a gang ground seemed good at the time and when I had everything out it looked great, but has turned out to be far to impractical.

Had I put that gang ground somewhere over on the side like down by the foot brake, it would have been fine. But no, where did I put it? On the column support behind the white plastic box that holds the speedo and the tach. How'd I get it back there with the box in the way? I didn't attach the lights until I put the box in. Then after I put the instrument panel in I just stuck the bulbs in their respective gauge holes and it was done. Yeah, until I tried to pull the instrument panel out and realized it only would come out half way.

So, today I remedied that problem that needed to have been done 25 years ago. Hey, better late than never. Now all the bulb wires have a foot of extra wire on them by cutting the ground wire where it went in behind the white plastic box and added a foot to it by soldering the extension to the end I had left after cutting it. Tomorrow I'll try to take some pics.

Then there were two wires that went back behind the white box that weren't connected to a light socket but instead went to two of my gauges, the fuel level and the volt gauge. They probably came from what was left of the harness after I cut off that gang plug that once plugged into the back of the printed circuit, that everyone has in their Square except guys who've replaced their factory gauges with aftermarket gauges.

Then I discovered there are two wires that go to a instrument light switch and those wires disappear behind the white plastic box to. So tomorrow I'll cut the terminal end off and add a few inches of wire to them and put another terminal end back on like the one I cut off. It's the type of terminal end that slides onto a spade end coming off the back of the switch. Probably the light bulbs that go to the speedo and the tach, they come on when I put on the instrument lights. I looked at all the other wires going to the instrument lights and those were the only two that were tight.

I also need to reattach my instrument light switch panel that came loose and after I fix those two wires I'll have enough slack to put the light switch panel back in. Like it is it can't be turned far enough to get it back into the A/C vent hole in the lower left corner of the panel. And how did I get it in there to begin with if the wires were to tight? I glued the switch panel I had made into the vent hole and when the glue was dried I plugged all the light terminals into the switches, so all the guages light up in pairs. I took all the A/C ducts out, there at the instruments, and converted them into panels for gauges and light switches.
 

Raider L

Full Access Member
Joined
Sep 1, 2020
Posts
1,757
Reaction score
821
Location
Shreveport, LA
First Name
William
Truck Year
1974
Truck Model
C10
Engine Size
355
Here's some pics of what I've been doing as described in text above. I hadn't taken the pictures of it all yet when I wrote the text yesterday, I wanted to finish it today so I could take my time and show what I needed to show.
You must be registered for see images attach
Atypical of how I had to connect a ground wire to the bulb socket since the instrument panel is not metal, and plastic is nonconductive although the chrome plated cab light gets it's ground from the plating on the plastic housing if I'm not mistaken. Sorry for the slight blurring. My camera seems to be doing that. It's not like the old camera's that were manual focus.
You must be registered for see images attach
The Black wires are grounds for the warning lights coming off the ground on the instrument bulb over there. You can see the black wire soldered to the bulb socket.
You must be registered for see images attach
Sorry again for the slight blurring, but this is some of the "piggy back" I did to lessen the number of power wires and ground wires for the instrument lights. Those are the switches for the instrument lighting that works in pairs. There are actually only three wires from the original printed circuit gang plug wires I used for the gauges. The rest are piggy backed bulb power and grounds. Best use of wire.
You must be registered for see images attach
Double
You must be registered for see images attach

Double
You must be registered for see images attach
Double...ignore. I'm still trying to figure out this new format with the pictures I want to post. Sometimes I get it right and sometimes I get this.
You must be registered for see images attach
Here you can see several things and I'll try to point them all out. You can see how I had to cut the original "cups" that held the factory meters. If you ever have yours out you'll see that they are tapered like a cone. You'd need to cut as much of that part off as is needed to be able to fit the gauge in the hole but not cut off to much then it will be to loose around the new gauge. You can't get a regular jig saw into the hole to cut it off. I tried several different blades and ended up using a "rasp" saw blade, which is a twisted round blade with "burrs" around the twist, like a rasp file. I couldn't use a jig saw. I ended up using a drill to power the rasp blade. Basically it melted the hole open, that's why the edges are so irregular. I measured the Autometer gauge housing and cut the original gauge cup holes out to approximate size of the Autometer gauge so it would go in the hole. You can see how close I got the cut out to the sides of the gauge housings. The gauges are being held in place by cutting the Autometer gauge support, the thing you place over the back of the gauge that holds it in place on the back of whatever kind of panel you are using. It was obvious that the whole support wouldn't work so I figured how much of it I needed and cut it off the support and placed the remaining "leg" on the gauge and still had to trim it until it worked as it was held in place by the nut that came with the gauge. The "leg" is pushing against the back of the plastic panel. Hey, this is basic hot rodding 101, whatever works to get the job done. Nothing is conventional.
 
Last edited:

Raider L

Full Access Member
Joined
Sep 1, 2020
Posts
1,757
Reaction score
821
Location
Shreveport, LA
First Name
William
Truck Year
1974
Truck Model
C10
Engine Size
355
More pictures.
You must be registered for see images attach
You can see how I just made a little panel for all the light switches. You can see the "piggy backing" a little better in this pic. It was like a light bulb coming on in my head getting this idea because I was going to run individual wires. Then this idea came to me, "Why not just piggy back these wires and jump from switch to switch with power and ground. That way it'll save me wire and is the right way to do this anyway. And besides all the switches will be getting their power from the same source."
Now, you brainy guys out there who do this for a living, you have to understand that I know very little about electricity. So when I get an idea, it's like a revelation! A big light coming on. "Yeah, that'll work!!"
You must be registered for see images attach
One of my little solder connections. I strip the end of the each wire just enough to push the ends together where they'll hold on together, then carefully put the solder into the joint. When I see there's enough solder to complete the connection I pull off and let it cool. I did take a pic of the shrink wrap on this joint but the white shrink wrap was to much and it was blurred from my camera not being able to focus on it good enough. But in this photo you can see white shrink wrap on the black wires below. That's where I added a foot of wire to extend the gauge bulb grounds. You'll see why.
You must be registered for see images attach
Here's why. Here's where I needed to have made the ground for all the gauge lights. down here on the emergency brake bracket where there was one already (the one with just two wires in a yellow connector). The new instrument light bulb ground is the one with the four wires in it. Amoung some other repairs I made in and around the switches this was about all.

Now I can see if I can fix my Amp. gauge while I have the fuel pressure gauge out. It'll be in the way some and I'd rather not have any more trouble than necessary.

Today I had the opportunity to take a closer look at where the wires from it went. And like I suspected, I did attach one wire to ground which you're not supposed to do, one of the two wire connector on the emergency brake bracket, and the other wire was soldered to that little 22 ga. black with white stripe wire from the original amp. gauge, that by the way didn't work either. Why I didn't follow the Autometer directions when I had the entire dash apart and could have run anything, I'll never know. I guess I thought it was convinent to have the factory amp. gauge wire already there, and again not reading the Autometer instruction sheet that clearly said to not attach any wire to ground, is just beyond me. And it was like what was said in a post I was reading last night, that the original amp wiring took a percentage of the difference between the volts and amps and that was what was indicated on the original gauge. The wiring has two 10 amp fuses in line and were in the main harness along the firewall in the engine compartment. That's where I had my Amp gauge hooked into. But I disconnected those wires from the back of the gauge today. The Autometer gauge I have is supposed to go straight to the positive post of the battery or near it with a #10 wire. So it's good that it never did work like I had it. That little bitty 22 gauge wire like the factory one that's in there, with it's two little 10 amp fuses would go up in smoke so fast you couldn't get the key off fast enough! Ha, ha, ha. It would be like, turn the key on, instant smoke, yell out, then as quick as is humanly possible turn the key off!! Afterwards it would be a lot of waving smoke away and look to see how much under the dash burned up, and noticing smoke coming from under the hood, get out and open it up and look to see what was fried there to. There would be this little smoke coming from inside the main conduit along the firewall. So I avoided all that scenario.
 
Last edited:

Raider L

Full Access Member
Joined
Sep 1, 2020
Posts
1,757
Reaction score
821
Location
Shreveport, LA
First Name
William
Truck Year
1974
Truck Model
C10
Engine Size
355
I have some #10 wire in black but not enough to wire to put it on the Autometer Amp. gauge leg. So I went to the Advance Auto Parts I usually use to look for some #10 wire. Well, they had a ton of different size wire but as big as they had was #12, in Red and Black, a couple of ten foot rolls. I'll reread the Autometer instructions and who knows maybe since the last time I read the instructions on the Amp. gauge install my memory as it is, maybe it was #12 wire.

@Ellie Niner, do you think a #12 wire would be okay to use on my Autometer Amp. gauge? I'm certainly not trying to dump the responsibility off on you to give me permission to use a wire size the instructions don't talk about, but what is the danger of using one wire size smaller? I mean a number 12 wire is big and there are #22 size wires carrying current in the wiring now on the truck, so what's the deal? I'll tell you, a #12 wire would be a heck of a lot more flexable than a dang #10 that's for sure.

The instructions do say to attach one wire on the Amp. gauge to the positive post of the battery, (the other to a 12v ignition source). Where I'm going to put that one wire is the battery side of the fusible link on the firewall where the ignition power wires all are. Isn't that okay? There IS a #10 ignition power wire there anyway and I'll put the terminal ring connector right on top of those wires. Those wires are connected to the battery cable just over on another side of the wiring. If that ain't full battery power there then I don't know a better place to put the wire other than right on the dang battery post!!

I'm sure people are wondering, "What's the big deal? He's splitting hairs about wire size. Just put a wire on the darn thing and let it go! Current will indicate and that's all you want isn't it?"
Yeah. I'm just real military about stuff like that and if it says #10 I'm going to really try to put a #10 on it. But also to, as I was taught in the Army, "situation dictates"! If it's okay to use a #12 then I'll use that. Besides that's all the store had, and it was expensive to boot.
 

Raider L

Full Access Member
Joined
Sep 1, 2020
Posts
1,757
Reaction score
821
Location
Shreveport, LA
First Name
William
Truck Year
1974
Truck Model
C10
Engine Size
355
I'm going to start a new post for this Amp. meter connection as it might help people understand what the ampmeter does and why would you have one in you truck, and how and why it does what it does. Most people don't have a ampmeter in their vehicle, only a voltmeter. The ampmeter tells you if the alternator is recharging the battery and at what rate compared to the load. It also tells you if your battery is holding a charge as the needle won't move back towards the center when the battery is charged back up by the alternator. If the ampmeter isn't moving back towards the center and is way over to "charge" past the 30 amp mark you know something is wrong. And worse if the ampmeter shows discharge and won't or isn't moving back to the center. It should indicate slightly to the charge side when the battery is normally being rechaged by the alternator. Under a discharge condition you know something is wrong with either the battery or the alternator if the needle isn't moving back to the center from discharge indication.
 

Matt69olds

Full Access Member
Joined
Jan 8, 2018
Posts
1,675
Reaction score
2,189
Location
Central Indiana
First Name
Matt
Truck Year
81
Truck Model
GMC 1/2 ton
Engine Size
455 Olds
If Autometer suggest 10 gauge, that’s the absolute minimum I’d consider using. Depend on the total length of the connections to the gauge, I’d strongly consider 8 gauge.

You can never have too big a wire, the only downsides to too big is cost and fitting the wire in the space you have. Considering the cost of your truck, verses the minuscule additional cost of 8 gauge verses 10, in my opinion it’s a no brainer.
 

ak4life

Member
Joined
Feb 22, 2021
Posts
42
Reaction score
9
Location
nevada
First Name
chris
Truck Year
81/84 gmc, 2001gmc, 2003 gmc, 2005 chevy
Truck Model
longbed squarebody, longbed 4dr extended cab, yukon sle, 4dr ext. cab
Engine Size
383, 6.0, 5.3, 5.3
Here's some pics of what I've been doing as described in text above. I hadn't taken the pictures of it all yet when I wrote the text yesterday, I wanted to finish it today so I could take my time and show what I needed to show.
You must be registered for see images attach
Atypical of how I had to connect a ground wire to the bulb socket since the instrument panel is not metal, and plastic is nonconductive although the chrome plated cab light gets it's ground from the plating on the plastic housing if I'm not mistaken. Sorry for the slight blurring. My camera seems to be doing that. It's not like the old camera's that were manual focus.
You must be registered for see images attach
The Black wires are grounds for the warning lights coming off the ground on the instrument bulb over there. You can see the black wire soldered to the bulb socket.
You must be registered for see images attach
Sorry again for the slight blurring, but this is some of the "piggy back" I did to lessen the number of power wires and ground wires for the instrument lights. Those are the switches for the instrument lighting that works in pairs. There are actually only three wires from the original printed circuit gang plug wires I used for the gauges. The rest are piggy backed bulb power and grounds. Best use of wire.
You must be registered for see images attach
Double
You must be registered for see images attach

Double
You must be registered for see images attach
Double...ignore. I'm still trying to figure out this new format with the pictures I want to post. Sometimes I get it right and sometimes I get this.
You must be registered for see images attach
Here you can see several things and I'll try to point them all out. You can see how I had to cut the original "cups" that held the factory meters. If you ever have yours out you'll see that they are tapered like a cone. You'd need to cut as much of that part off as is needed to be able to fit the gauge in the hole but not cut off to much then it will be to loose around the new gauge. You can't get a regular jig saw into the hole to cut it off. I tried several different blades and ended up using a "rasp" saw blade, which is a twisted round blade with "burrs" around the twist, like a rasp file. I couldn't use a jig saw. I ended up using a drill to power the rasp blade. Basically it melted the hole open, that's why the edges are so irregular. I measured the Autometer gauge housing and cut the original gauge cup holes out to approximate size of the Autometer gauge so it would go in the hole. You can see how close I got the cut out to the sides of the gauge housings. The gauges are being held in place by cutting the Autometer gauge support, the thing you place over the back of the gauge that holds it in place on the back of whatever kind of panel you are using. It was obvious that the whole support wouldn't work so I figured how much of it I needed and cut it off the support and placed the remaining "leg" on the gauge and still had to trim it until it worked as it was held in place by the nut that came with the gauge. The "leg" is pushing against the back of the plastic panel. Hey, this is basic hot rodding 101, whatever works to get the job done. Nothing is conventional.
Just an fyi on cutting bezels, the easiest way and quick also is a hacksaw blade by it self....wrap duct tape around one end for your hand and they come out nice.....no pic at the moment....really do not feel like pulling that rats nest out right now....lol
 

Forum statistics

Threads
35,534
Posts
747,419
Members
24,453
Latest member
jbengfort
Top