unwelcome effects from a not-so-bright idea

[martybose]

Tonight I took my daughter out for dinner in the 47, then dropped her off at the barn where her horse is boarded. it was dark out as I started down the steep, narrow, twisty single lane driveway going down to the twisty, unlit country road. The halogens were blazing away, but I thought to myself, "I wonder what it would be like if I turned on my fog lights?" I've had them on before, but never in full darkness.

So what the hell, let's find out! Turned on the foglights, and milliseconds later there is a sizzling sound and all of the lights go off! The engine was still running, but no lights anywhere. I've owned this car for 14 years, and have never had a total failure like this! I'm guessing that I blew a fuse on the headlight switch (??), but I wasn't anywhere I could troubleshoot it. Fiddling with every switch revealed that the only working outside light was the turn signals, even the stoplights were dead. So I turned on one turn signal and carefully drove home, torn between staying off of the main drags and the knowledge that all of the side roads were unlit, so I would be invisible while on them. Finally made it home (about 12 miles), put the car in the garage and shut off the battery until I can figure out what went wrong. The headlights are on relays, so it must have been something to do with the foglights; I'll figure it out this weekend.

Whew!!!!

Marty

[rearview]

I had the same thing happen a month and a half ago, coming home from the car club party at midnight. Had the highbeams on, cruising down one of Wisconsin's many Rustic Road when poof... darkness. No moonlight... nothing. Only had brake lights. drove slowly and carefully about 1.5 miles to a wide spot then fixed the burned wire with no tools by the light of my cell phone (and no reading glasses!)

[Normspeed]

Yeah, sounds like you let all the smoke leak out of something there Marty!

[steveplym]

Well at least the moral of the story is don't try something new unless you get closer to home.

I've done things like that too and usually look back and go "Why did I do that?"

Good luck on figuring out what it is Marty. Sounds like a short in the wiring.

[rearview]

Probably another cse of 60 year old wires, just like mine was

[martybose]

Probably another cse of 60 year old wires, just like mine was

That's the one thing it can't be; I replaced the entire wiring harness 6 or 8 years ago.

Marty

[randroid]

Gents,

When I rewire my '48 next Spring I'm going to install a relay for the lights just to avoid such a situation. I don't think I could handle being without lights quite so gracefully as did you.

-Randy

[Young Ed]

I drove all the way home from detroit with no lights. Was a little nerve wracking! Thankfully it was dry and sunny those 2 days. Mine turned out to be the dimmer wiring got out of place and the clutch pedal rubbed a short in them. The lights would work until you tried to shift to leave.

[BobT-47P15]

Marty......it sounds as if maybe you need another fuse, in the line for the

fog lights.

Are they hooked up to the headlight switch and wiring for the headlights?

I would think they could be hooked up at another location by themselves

as all they require is power and ground. Probably have their own switch

to turn off/on.

I have a set of n-o-s Dietz fog lights but have never gotten around to

putting them on the car. I would connect them to their own place.

[martybose]

Gents,

When I rewire my '48 next Spring I'm going to install a relay for the lights just to avoid such a situation. I don't think I could handle being without lights quite so gracefully as did you.

-Randy

I've got relays, but they don't work if you kill the signal voltage, which still comes from the headlight and dimmer switches.

On the other hand, maybe I should throw a jumper wire with alligator clips in my spares kit; that way I could hotwire the low beam relay from the solenoid if I blew the fuse again.

Now all I need is a similar fix for the taillights .....

Marty

[martybose]

Marty......it sounds as if maybe you need another fuse, in the line for the

fog lights.

Are they hooked up to the headlight switch and wiring for the headlights?

I would think they could be hooked up at another location by themselves

as all they require is power and ground. Probably have their own switch

to turn off/on.

I have a set of n-o-s Dietz fog lights but have never gotten around to

putting them on the car. I would connect them to their own place.

Mebbe. It's been a while since I messed with the foglights, so I'll have to refigure out what I did. I think they are wired to get power from the headlight switch, so turning off the headlights will kill the foglights too.

I'll be diving into this whole deal Saturday morning, and will report on cause, effect and repair.

Marty

[martybose]

I forgot to mention another side effect. At one point I thought to turn on my two spolights and aim them forward to at least make me visible. No such luck; the power switches in the handles apparently aren't real good, and they wouldn't stay on. If I wiggled the switches a bit they would come on for a little while, but that wasn't something I could manage while trying to drive home.

Figuring out a fix for the spotlight switches has been added to "The List".

Marty

[martybose]

Well, I found the cause of my problems today. It turns out that I had blown both the foglight fuse AND the headlight fuse. Ididn't see anything out of place under the dash, so put in a headlight fuse first, everything worked. Then put in the foglight fuse, turned them on and pfft!! blew the headlight fuse again.

So I started tracing wires, and found the problem in front of the radiator. When I installed the electric pusher fan on my radiator, I switched from the straight Plymouth horns to the 90 degree Dodge horns to gain some fan clearance. It turned out that the bell of the drivers side horn was leaning against the extra terminal strip that I had put in 10 years ago for the foglights and turn signals, specifically again the hot lead for the foglights! So the instant I turned on the foglites, away went the fuses.

Apparently the load on the headlight switch is greater than 10 amps, because the 30 amp fuse on the headlight switch blows before the 20 amp one on the foglight switch. Interesting, considering that I am running relays for the headlights.

I didn't feel like trying to relocate the terminal strip or the horn, so I just split a vacuum hose, put it on the offending edge of the bell, drilled a couple of small holes and tiewrapped it in place.

Boy, it's sure nice when a mystery suddenly makes sense!

Marty

[BobT-47P15]

Marty......one more example of how the craziest things can happen on a

car. But the good news is you found it and fixed it (for now).