Wiring Dash and instrument cluster 1940

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stevejenkins2010

New member
]Hello, I’m a new member here. I’m looking for any advice on how to install a dash wiring harness for my 1940 standard Sedan. I have a new Dash wiring harness, but looking for advice on installation. Should I remove dash, or front seat ? Is there any step by step guide in a mechanics manual?

I rewired the headlights already, took a good bit of time, and would appreciate any advice before tackling this new project....thanks!!
 

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I personally hate trying to do anything from under the dash. If you are going to go that route definitely take the seat out. On both my deluxe wagon and V8 (standard) coupe I wired everything to the dash on my bench, tested all dash lights, then fed the wire through the firewall hole as I reinstalled the dash. This is easier if the steering wheel is off if you do it my way. That worked for me. I know everyone is different, I am now almost 70 and that also factored into my decision. If you are young, relatively small and limber it can be done with the dash installed but if you do that prepare to use lots of bad language and have a very stiff neck.
Good luck however you proceed.
Oh and welcome to the Barn! Make an album of pictures, then people can click on your avatar and see your project/cars.
 
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When I rewired the 42 Ford I decided to remove the entire dash assembly for this portion of the job. This allowed me to remove every dash component and clean everything thoroughly. Also it’s the perfect time to replace all the little dash and instrument bulbs. I did all the dash prewiring that was possible to do.

Unfortunately, the final harness hookups still have to be done after reinstalling the dash. This meant lying on my back, wedged under the steering wheel at times, looking upward. If I had to do it again I would remove the front seat and perhaps the steering wheel as well. It didn’t help that I did the job in the summertime.....
 
First, disconnect your battery. Be sure all the required rubber grommets are installed in your firewall for the wiring. Take plenty of BEFORE photos of the old under dash wiring so you can clearly see where it's connected. Leave the dash in your car. Remove the front seat and steering wheel. Then lay a thick blanket, quilt or sleeping bag and pillow (for your head) on the floor board. I know this sounds silly but, wear safety glasses and cover your mouth with a face mask just in case you drop a little dash screw or nut while your laying face up on your back. You don't want to accidently swallow a gauge nut or connector that you drop during the installation. One final thought. Use a wire tie to support your speedo cable so it feeds straight into your speedometer. This relieves stress on the cable. I don't think there's any special step by step procedure other than making sure you follow the color code. It's not OEM but I covered the dash cluster hold down clamps with electrical tape so they won't squeak. Don't over tighten these or you'll dimple your dash sheet metal. Here's some photos. If you do remove your dash be sure to fold a piece of electrical tape over the entire top edge where it rests against the window frame to prevent squeaks. OEM used the old style cloth electrical tape butIi don't know if it's still available. Also, don't forget to install welting between windshield garnish molding and top of dash.
 

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I installed my new dash harness with the dash and seat in place. I had what was left of my factory harness as a guide and used the wiring diagrams to verify. It really was not a lot of connections. I pulled the gauge cluster out to access those connections and the dimmer. My glovebox was not in place either.

That being said i'm only middle aged, tall and lanky, and still pretty limber. Removing the seat would probably make things much more comfortable for the install.
 
19Fordy said:
If you do remove your dash be sure to fold a piece of electrical tape over the entire top edge where it rests against the window frame to prevent squeaks. OEM used the old style cloth electrical tape butIi don't know if it's still available.
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Yes, the old electrical tape is still available. Search for "friction tape" on Amazon or other sources.

Ken
 
I agree with others. Remove the dash and do the pre-wiring first. Then remove the front seat so you can lay on your back and complete the final connections. I have done all the connections with the dash in place, front seat removed. It depends on your age and agility.
 
Removing the dash is a " troublesome" as you have to remove the windshield garnish moldings which can be tricky. That's why I prefer to leave dash in car.
 
I would give it a try before removing the dash.
I’ve done it both ways and don’t recommend removing the dash.
Even though I’m 83 I don’t. But age has nothing to do with it - It depends on how agile you are. I don’t remove the seat, but I highly recommend it.
Glasses are a must, a face mask is recommended.
Do not, I repeat do not use a drop light with a regular old sty light bulb that gets hot unless you like the smell of burning flesh.
I have dropped them on my forehead several times.
Once on a very low mileage 51 Mercury I dropped the drop light on the floor just behind the accelerator pedal right on the plastic heel pad that is molded into carpet.
Before I could get twisted around and grab the light it melted a big hole in the good-as-new carpet. It’s the only spot on the car that isn’t perfect.
You’re going to be happier with the job if you put in extra effort to keep from burning yourself or getting crap in your eyes and mouth.
Early this winter I took a speedo and clock out of a 53 ford covert.
There was mouse crap up there, I hate the taste of mouse crap.
 
On my 41 pickup, which uses the same instrument cluster, the cluster can be pulled out through the dash hole and worked on more easily. The only pre-requisite is that the speedo cable be removed first.
I show the cluster being removed and refitted in one of my videos. It's the one where I fit a fuel gauge in my 41 pu.

Please shout if you want a link.

Mart.
 
Probably no big surprise to many of you but (against popular opinion) I'd suggest installing the harness with the dash in place. Yeah, remove the seat.
Of course, much depends on agility.
If the original poster is young enough to bend and twist and actually see, well, leave the dash in.
I install the harness to an already installed dash on my restorations (no seat) as I can then route the wires to my satisfaction.
 
Q: Did the factory install all dash-related components on the dash first (wiring, light bulbs, switches, glove box/liner, pull knobs, ash trays), then install the whole thing as an assembly as the body rolled down the line? Moral of the story - think of how the assembly line guys put it all together, especially since dashes aren't that hard to remove/install on a pre-'50s car. JMHO.
 
I have rewired dozens of classic/vintage cars and rarely removed the dash to wire it first. Always wire all of the car and then do the dash last. Often removed the front seat and occasionally the steering wheel. Lay out flat with your head on a pillow against the firewall, a good light and have as many of your tools close to you on the floor beside you. Im 74 now and not as flexible as I once was so generally don't do it anymore. Regards, Kevin.
 
I have installed a few looms for mates lately. Having the gage cluster out of the car at least means you can clean up the gages (and saves my ageing back a little too)

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fortyonerag said:
Sorry about the big pics. How did that happen?
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I get the same effect when someone emails a picture from their phone. There is something on the phone that allows resizing the picture to make it appear normally. Someone who is not a troglodyte like me can probably jump in and help.
 
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