The Ford Barn

Woodie1 · 07-08-2022, 01:41 PM

We have a 29 Model A that has an issue with the head light switch bulb I think. There may be several problems going on. High & low beams come on as they should. Brake lights work as they should. Tail lights & cowl lights don't come on. There is a brief flicker of the tail lights when moving the light switch handle but no light. The car has a turn signal setup which was working but now the flasher is clicking but no turn signals front or rear. When the signal lever is moved to signal left or right, the little green lights don't come either. Aside from the turn signal issue, it seems there is a problem with the light switch bulb. The light switch doesn't have a very positive click when moving to the various lighting positions. It makes me think the plastic plate with the contacts isn't far up enough to make a good contact. What are your thoughts & a fix?

Joe K · 07-08-2022, 08:36 PM

The Model A Ford had no turn signals originally. Think "hand signals" out the window.

If yours is a '29, there is a possibility that yours has the earlier "type H" headlights. If they're original and intact you can tell these by looking at the lens: the type H lights have "vertical flutes" and no half-round upper half.

If yours is a type H, then you have a special switch which involves a special wiring harness. The special switch has positions for "Off","High" and "Low" and that's it. Your switch handle (center of the steering column) may be marked thus.

If yours is a later '29 then you likely have "Two-light" headlights. These can be seen by the lens which DOES have the half-round lens pattern in the upper half of the glass. These would be more common and where Ford went for the rest of production until 1931.

Two-light headlights have switch positions for "Off", "Low", "High", and "Park". The Two-light designation comes from the fact that the front lights have TWO bulbs, one for High-Low and one off center for the Parking Light.

The original switch pod for the Two-light setup has been reproduced. The reproductions are none too good and suffer from design problems including: detent positions "sunk" too deep in the plastic, insufficient contact height to meet the detent contacts, insufficient spring strength (i.e. switch tends to move when you move the steering wheel.) Wiggling the switch pod makes the light "blink" or go out altogether.

For either Type H switch pod or Two-light switch pod it's best to get an original switch in good condition and use that.

Now many have added "accessory" column clamped on "directional" switches located about where they are in a modern car. These date to the late 30s or later and are usually "hotwired" into the lighting system. Now I can't tell you how this is done best or what your installer did which may be less than optimal, but I'll have to leave this to you to figure out.

You want to start with the usual Model A Wiring Diagram, seen at https://sacramentocapitolas.org/2017...iring-diagram/ This diagram is for the Two-light system although the Type H diagram is similar. Search "Model A Ford Wiring Diagram" and you'll come to both.

Another issue with the Model A Lighting System commonly seen (and this is both Type H and Two-Light variants) is that the modern wiring harnesses don't have the correct "bullet-end" fittings which tend to inhibit the contact at the rear of the headlights where the stainless conduit holds the wiring/plug in place. The harnesses are provided with a "pressed on" bullet shape contact end while the original ends were solid brass and soldered onto the wire. The deficient harnesses CAN be modified with new bullet ends and (perhaps) solve the issue. Many get past the problem by variously "hard wiring" their headlights to the internal wires usually with solder connections. When the stainless conduits are in place you don't see the non-original modification.

The headlight sockets have been reproduced but many of the early reproductions "melted" under the heat of the commonly used 35-21 CP bulbs. Today's reproductions are better - with either bullet-end rework or hard wiring they can be quite reliable.

Another issue is one of headlight ground. Original ground was supposed to be by the headlight bar/fenders/chassis. Most "hard wire" an additional ground wire directly from the light sockets to somewhere on the chassis passing through the crowded conduit.

So therein lies the Model A electrical system in as few words as I can muster. It is probably the weakest part of the original design but very easily "adapted" - if you're sure of what you're doing.

Look into including the accessory "fuse" which is located on a small plate just above the starter switch. Without this fuse, a momentary short can take out your ammeter which in the original design was to act as "fuse" - but self destructs in the function.

Good luck.

Joe K

Woodie1 · 07-08-2022, 08:53 PM

I'm sure this switch is an old repro or original. I'm sure it will work, I just need to get a closer tighter contact to happen inside so there is a positive connection. Just more work to do.

Ted Duke · 07-09-2022, 06:26 AM

"High & low beams come on as they should. Brake lights work as they should. Tail lights & cowl lights don't come on. There is a brief flicker of the tail lights when moving the light switch handle but no light. The car has a turn signal setup which was working but now the flasher is clicking but no turn signals front or rear. When the signal lever is moved to signal left or right, the little green lights don't come either."

Different systems NOT working. Check your ground engine to frame.

Joe K · 07-09-2022, 10:02 AM

I mentioned "The reproductions are none too good and suffer from design problems including: detent positions "sunk" too deep in the plastic, "

This is actually a defect of the available wiring harnesses. As the wiring harnesses are sold they include the plastic "plate" from where this issue arises.

You may have an original switch, but the repop plate may be what is introducing issues.

The solution to this can be to find an original plate and solder it in place of the repop, or modify the repop to improve contact.

Original switches as good as they are perceived CAN have an issue of the fiber, laminated "core" of the moving parts of the switch which can "delaminate" due to repeated exposure to water (it is open to splash from the road) and the metal crimped on parts come loose. Nothing is forever, of course.

My original original switch was a glob of previously sodden cardboard.

Joe K

katy · 07-09-2022, 10:11 AM

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Have you checked the bulbs?

jrelliott · 07-09-2022, 12:27 PM

Have you checked the light switch retainer clip to be sure is installed correctly? Or is the contacts clean on the bottom plate where the wires to headlights, cowl lights and tail lights are connected? JoeK's comments about the headlight wiring is right on. The connectors are a real problem.

Woodie1 · 07-09-2022, 03:25 PM

We have most of the issues resolved now. We put a different upper switch body on. Doing so, we now have tail lights. The clicking signal relay stopped clicking (don't know why) & we did find the cowl light bulbs were both blown. Not sure what caused this either. All turn signals work as they should. We just have to keep an eye on things to see if the problems come back. The light switch feels more positive now when moving it to the different light options.

07-08-2022, 01:41 PM	#1
Woodie1 Senior Member Join Date: Mar 2011 Location: W. Mich. Posts: 471	Head Light Switch Bulb We have a 29 Model A that has an issue with the head light switch bulb I think. There may be several problems going on. High & low beams come on as they should. Brake lights work as they should. Tail lights & cowl lights don't come on. There is a brief flicker of the tail lights when moving the light switch handle but no light. The car has a turn signal setup which was working but now the flasher is clicking but no turn signals front or rear. When the signal lever is moved to signal left or right, the little green lights don't come either. Aside from the turn signal issue, it seems there is a problem with the light switch bulb. The light switch doesn't have a very positive click when moving to the various lighting positions. It makes me think the plastic plate with the contacts isn't far up enough to make a good contact. What are your thoughts & a fix?

07-08-2022, 08:36 PM	#2
Joe K Senior Member Join Date: Jul 2010 Location: Cow Hampshire Posts: 4,188	Re: Head Light Switch Bulb The Model A Ford had no turn signals originally. Think "hand signals" out the window. If yours is a '29, there is a possibility that yours has the earlier "type H" headlights. If they're original and intact you can tell these by looking at the lens: the type H lights have "vertical flutes" and no half-round upper half. If yours is a type H, then you have a special switch which involves a special wiring harness. The special switch has positions for "Off","High" and "Low" and that's it. Your switch handle (center of the steering column) may be marked thus. If yours is a later '29 then you likely have "Two-light" headlights. These can be seen by the lens which DOES have the half-round lens pattern in the upper half of the glass. These would be more common and where Ford went for the rest of production until 1931. Two-light headlights have switch positions for "Off", "Low", "High", and "Park". The Two-light designation comes from the fact that the front lights have TWO bulbs, one for High-Low and one off center for the Parking Light. The original switch pod for the Two-light setup has been reproduced. The reproductions are none too good and suffer from design problems including: detent positions "sunk" too deep in the plastic, insufficient contact height to meet the detent contacts, insufficient spring strength (i.e. switch tends to move when you move the steering wheel.) Wiggling the switch pod makes the light "blink" or go out altogether. For either Type H switch pod or Two-light switch pod it's best to get an original switch in good condition and use that. Now many have added "accessory" column clamped on "directional" switches located about where they are in a modern car. These date to the late 30s or later and are usually "hotwired" into the lighting system. Now I can't tell you how this is done best or what your installer did which may be less than optimal, but I'll have to leave this to you to figure out. You want to start with the usual Model A Wiring Diagram, seen at https://sacramentocapitolas.org/2017...iring-diagram/ This diagram is for the Two-light system although the Type H diagram is similar. Search "Model A Ford Wiring Diagram" and you'll come to both. Another issue with the Model A Lighting System commonly seen (and this is both Type H and Two-Light variants) is that the modern wiring harnesses don't have the correct "bullet-end" fittings which tend to inhibit the contact at the rear of the headlights where the stainless conduit holds the wiring/plug in place. The harnesses are provided with a "pressed on" bullet shape contact end while the original ends were solid brass and soldered onto the wire. The deficient harnesses CAN be modified with new bullet ends and (perhaps) solve the issue. Many get past the problem by variously "hard wiring" their headlights to the internal wires usually with solder connections. When the stainless conduits are in place you don't see the non-original modification. The headlight sockets have been reproduced but many of the early reproductions "melted" under the heat of the commonly used 35-21 CP bulbs. Today's reproductions are better - with either bullet-end rework or hard wiring they can be quite reliable. Another issue is one of headlight ground. Original ground was supposed to be by the headlight bar/fenders/chassis. Most "hard wire" an additional ground wire directly from the light sockets to somewhere on the chassis passing through the crowded conduit. So therein lies the Model A electrical system in as few words as I can muster. It is probably the weakest part of the original design but very easily "adapted" - if you're sure of what you're doing. Look into including the accessory "fuse" which is located on a small plate just above the starter switch. Without this fuse, a momentary short can take out your ammeter which in the original design was to act as "fuse" - but self destructs in the function. Good luck. Joe K __________________ Shudda kept the horse. Last edited by Joe K; 07-08-2022 at 08:42 PM.

07-08-2022, 08:53 PM	#3
Woodie1 Senior Member Join Date: Mar 2011 Location: W. Mich. Posts: 471	Re: Head Light Switch Bulb I'm sure this switch is an old repro or original. I'm sure it will work, I just need to get a closer tighter contact to happen inside so there is a positive connection. Just more work to do.

07-09-2022, 06:26 AM	#4
Ted Duke Senior Member Join Date: Mar 2012 Location: Fairfield, Virginia Posts: 615	Re: Head Light Switch Bulb "High & low beams come on as they should. Brake lights work as they should. Tail lights & cowl lights don't come on. There is a brief flicker of the tail lights when moving the light switch handle but no light. The car has a turn signal setup which was working but now the flasher is clicking but no turn signals front or rear. When the signal lever is moved to signal left or right, the little green lights don't come either." Different systems NOT working. Check your ground engine to frame.

07-09-2022, 10:02 AM	#5
Joe K Senior Member Join Date: Jul 2010 Location: Cow Hampshire Posts: 4,188	Re: Head Light Switch Bulb I mentioned "The reproductions are none too good and suffer from design problems including: detent positions "sunk" too deep in the plastic, " This is actually a defect of the available wiring harnesses. As the wiring harnesses are sold they include the plastic "plate" from where this issue arises. You may have an original switch, but the repop plate may be what is introducing issues. The solution to this can be to find an original plate and solder it in place of the repop, or modify the repop to improve contact. Original switches as good as they are perceived CAN have an issue of the fiber, laminated "core" of the moving parts of the switch which can "delaminate" due to repeated exposure to water (it is open to splash from the road) and the metal crimped on parts come loose. Nothing is forever, of course. My original original switch was a glob of previously sodden cardboard. Joe K __________________ Shudda kept the horse. Last edited by Joe K; 07-09-2022 at 11:16 AM.

07-09-2022, 10:11 AM	#6
katy Senior Member Join Date: Jun 2015 Location: Red Deer, Alberta Posts: 5,046	Re: Head Light Switch Bulb Sponsored Links (Register now to hide all advertisements) Have you checked the bulbs? __________________ If you don't hear a rumor by 10 AM, start one!. Got my education out behind the barn!

07-09-2022, 12:27 PM	#7
jrelliott Senior Member Join Date: May 2010 Location: Pine, AZ Posts: 794	Re: Head Light Switch Bulb Have you checked the light switch retainer clip to be sure is installed correctly? Or is the contacts clean on the bottom plate where the wires to headlights, cowl lights and tail lights are connected? JoeK's comments about the headlight wiring is right on. The connectors are a real problem.

07-09-2022, 03:25 PM	#8
Woodie1 Senior Member Join Date: Mar 2011 Location: W. Mich. Posts: 471	Re: Head Light Switch Bulb We have most of the issues resolved now. We put a different upper switch body on. Doing so, we now have tail lights. The clicking signal relay stopped clicking (don't know why) & we did find the cowl light bulbs were both blown. Not sure what caused this either. All turn signals work as they should. We just have to keep an eye on things to see if the problems come back. The light switch feels more positive now when moving it to the different light options.