The Stovebolt Site Forums The Shop Area The Electrical Bay 1951 instrument lights

Might as well journey deeper down this electrical rabbit hole while it’s top of mind. Just recently got turn signals working, before I tie things up and out of sight under the dash, I’d like to see if I can get instrument lights working.

Shop manual wiring diagram show all the dash instrument circuits tying into a common point along the instrument circuit between the headlight switch and the ignition switch.

Is there some kind of terminal block or something under there? I can think of any number of ways to replicate the same circuit…just curious what the factory did, and what’s practical when re-doing it.

Check the headlight switch ,my truck I used to have to turn the switch for dimming the lights back and forth to get the dash lights to work . From sitting the contacts corroded on the dimmer contact and spring on the switch.There is a post by Jon G on how to repair ,service the switch.

Most/ all of the instrument wires are just dangling from a previous owners’ attempt at something.

I guess I could jumper each individual wire (once positively identified) to the switch to see what works and what doesn’t. Just wondering how the original circuit was all put together and the best way to make it right moving forward. I’m definitely not concerned about originality for hidden wires under the dash. Reliable and safe is what I’m after.

Gauges have to be removed to check bulbs I guess? Shop manual is strangely silent on this topic.

If my memory serves me, one light for the gauge cluster, one for the speedometer, and one for the ignition switch, (although seems like one of the gauge housings had two bulbs). I installed a small terminal block under the dash, all the light sockets to it, and then one wire from the terminal block to the headlight switch terminal. I solder and heat shrink all my connections....cause I'm o.c.d. like that. Whether this was like factory or not, is beyond me.....it works, is solid, and I don't think I'll ever have to fool with it again. As most of us here, I'm not too thrilled about having to work under the dash, particularly with everything installed. A small telescoping mirror goes a long way here.

The bulb holder/socket snaps in a hole on the back of the gauge housings, so no, you do not have to remove the gauges. Seems like I got all the bulb sockets and bulbs from O'Reillys.

Shop Manual doesn't show you much, but the Factory Assembly Manual Has some really good pictures of all of it.

Bulb sockets twist out? Or just pull out?

The bulb sockets just pull out. In addition to what Mike said, there's a bulb for high beam indicator. I believe it's at the top center of the gauge cluster.

Where is the ignition light?

It goes in the bracket holding the ignition switch.

Found this in an old thread.

The dash light bulb wires join the harness and head back OUT the firewall? Is that what I’m seeing?

Instrument and Ignition switch bulbs go to headlight switch. The high beam indicator has to go thru firewall to connect to a high beam wire or to headlight dimmer.

There are two bulbs per gauge cluster, one for the ignition switch. The five dash lights are just pigtailed from one to the other and connected to the headlight switch. The high beam indicator, at the very top of the speedometer cluster is attached at the hi side of the dimmer switch.

The first photo is the headlight terminals. The second shows the speedometer cluster, what the socket looks like and the ignition switch bulb location.

It is much easier removing the switch and clusters from the dash and just dropping them down with the wiring attached to work on them. Access to the clusters can be a bit easier by removing the radio speaker grille.

Excellent pic. That helps. I do have the shop manual wiring diagram and that other drawing thing helps visualize. But your pic helps a lot.

How does a guy get the speaker grill out?

There are four nuts on the corners and maybe two in the center. If I remember correctly, remove the ones on the top and just loosen the bottom and the grille will just slip out from the bottom moulding. Use a 1/4” drive socket from the back of the dash. You can reach them pretty easily. I think they are 3/8” or 11/32”.

JW51 You should have 5 lamp sockets under the dash 2 for the gage cluster 2for speedometer cluster 1 for key mount bracket so you can turn on dash lights to see where the key slot is. The 2 clusters have snap-in holes left and right,after practice you can reach in with one hand and change the bulb. Headlight knob counterclockwise dims CW brightens,probably be kinda coroded at first will get better. I take a can of WD forty, remove knob and stem by depressing that button on top of the switch,just pull it out-insert your WD 40 tube as deep as it will go into the switch,spray on your way out. This will lube the switch, lube the point on your stem push back in will re-engage the switch. Might spray the rheostat coil at the front of the switch too.

JW51 tried

JW51 Try again

I've got the loom from my 51 3600 on the kitchen table and that connection node for the instrument lights could be original (& a bit burnt) on mine. I've got six cables crimped and soldered into one fitting. Any original insulation is long gone! Photo attached for interest.

There ya go. Exactly what I was looking for. Thanks!

I made my own harness for my 51 from the original pattern. The feeds to the five lights are joined inside the harness and only one wire goes back to the light switch. I found that removing the light switch and popping the sockets out gave me access to the wiring. I also removed the radio grill. Taking one of the pods out too is helpful. The original harness does not have a lot of spare wire or slack and that makes it secure and self supporting.