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I noticed tonight that my taillights were very dim compared to normal. After a little bit of troubleshooting, I noticed that my taillights are good as long as my instrument/map light switch is in the off position. If I switch that to either the instrument light or map light position, the taillights get noticeable dimmer. There does not seem to be any impact to the headlights brightness.

Looking at the wiring diagram that I put together some time ago in conjunction with the original Packard diagrams, the problem is not obvious. Has anyone else experienced this? My only thought right now is that it may be a bad/dirty ground connection, but I’m not sure where.

Thoughts?

I'd get out a multi-meter and see if/what the voltage drop is taillights with the maplight on/off.

There is a possibility that there is some kind of minor short it that map light switch.

If you see a drop when the swtich is in either position, then try removing the switch from the dash and let it dangle so it's no longer grounded, and see if the problem persists.

If it suddenly goes away, then the switch has some kind or minor internal short.

Power follows the easiest path. So a minor short in the swtich and/or combined with dirty grounds or dirty connections somewhere between headlight switch and the taillight sockets could cause the issue.

good Idea on checking out the switch, Kevin. I have added this to my list.

In the meantime, I made the new support brace for the air cleaner. I’ll prime and paint it when I take things back apart to pull the manifold.

The brace looks excellent! I have one for a 1940 110 which looks much the same so yours is a nice, authentic-looking replacement.

Thanks, Don.

So, today was a really good day. There were some frustrations along the way, but another “winter project” is complete.

But first, a huge THANK YOU to to Henry (CLi55er). I could not have completed this project with out all the help…absolutely priceless!

After talking to Henry this morning and while having him on the phone, I got the car started with the “new” Carter WD-0 carburetor. That was huge! But, I quickly realized I had a couple fuel leaks at the newly installed glass bowl fuel filter.

I tried tightening the connections and that took care of one but not the other. In the end, Greg (my son) and I concluded that I had failed with my double flares for the new fuel lines. With that, and a few practice flares, I remade the lines and we got them installed. It probably took longer than it should have, but we were talking and watching the Chiefs game as well. In the end the second attempt at the fuel lines were a success and Greg and I had a fun day together.

Then, it was back to the carburetor. I had to adjust the throttle linkage (shorten) quite a lot when installing the new carb. Even after the choke opened fully, it was still idling a little fast. We adjusted that and got it at a nice idle. Time for a test drive.

Now, I knew this already, but clearly got over confident. ALWAYS do a lap around the block for a test drive before getting on the highway (35mph speed limit). I didn’t do that and when I went to go, the car decided otherwise. It was everything I could do to keep it going. So, we limped back home and the text messages to Henry started again. We decided that the issue had to be with the accelerator pump and were discussing how to adjust that. That’s when Greg looked at the carb and realized that I must have knocked that linkage loose when installing the choke tube. Well, that explained a lot! We reconnected that and secured the retainer clip and back for another test drive.

This time, I did go around the block first and everything seemed good. We then drove up to O’Reillys to return the rented flare tool followed by an extended test drive. Wow, what a difference. The car has a LOT more “get up and go”. I couldn’t be happier.

So for the day, I:
1. Got the car with the new carb up and running,
2. Had a great day with my son,
3. Really strengthened a relatively new friendship with Henry.

You put that all together, it’s a great day!

Next up….pull the carburetor back off so i can pull the manifolds and I can get the exhaust manifold ceramic coated. Then, while I’m waiting on that, I’ll try figuring out the tail light issue.

Back to my tail light dimming issue when I turn on either the instrument lights or map lights….

The map/instrument light switch itself seems to be good. I measure 0.2 ohms when switched to each position.

I did discover that the main headlight switch seems to have a role in the mystery. I’ll have to do more research, but here is what I’ve found so far.

1. Turn on the lights (main headlight switch) with instrument/map light switch in OFF postion - tail lights are good.
2. Turn on the instrument or map lights - tail lights dim, headlights are still good.
3. Turn the instrument/map light switch back OFF - tail lights remain dim, headlights are still good.
4. Turn the main headlight switch OFF - all lights off.
5. Turn the main headlight switch ON (any position) - tail lights and headlights are all good again.

This is very repeatable. So, I don’t think the issue is with the instrument/map light switch.

When I have some time, I’ll pul off a tail light lens and check the actual voltage along with check the ground connection between the tail light ground and a know solid ground near the headlight main switch.

More to come…