Topic: Headlight Switch

[ChrisV289]

Does anyone know what the difference is between the 3 headlight switches offered for 64-65 Mustangs?  My headlights keeping going on and off and I want to replace the switch (2nd switch)...a lot of the places around here aren't aware of three switches offered.  I'd like to know if it is an internal wiring thing with the switches or is it the difference of the brackets that hold them to the dash....Mine of course is the switch that was offered only from August until November....


Thanks,
Chris

[CharlesTurner]

What kind of voltage regulator (the one in the engine bay) are you using?

[ChrisV289]

Charles,

I am using a later (67+) voltage regulator but changed the top to make it look like a 65 one.  My interior lights would pulse a lot more with the older style voltage regulator...With the later stylen they don't pulse as much...

[CharlesTurner]

It's pretty common that headlight switches are the culprit of the pulsing lights issue, but I have found that the issue can also (sometimes) be resolved by making absolutely sure all the ground contacts are good and using a later Motorcraft electronic-style voltage regulator.

[ChrisV289]

I changed the voltage regulator to the electronic one not too long ago but the headlights keep going on and off...Kind of scary to drive it at nights....The fog lights stay on thankfully but I can't see the road to well...If I change the headlight switch again, is there a difference between the three headlight switches (prior to Aug 64, Aug 64-Nov 64, and after Nov 64) or are they all the same?

[CharlesTurner]

I don't know the differences.  Check with Randy (aka midlife), he might be able to help.

[midlife]

I thought the issue with headlights going on/off rapidly was due to the dimmer switch, not the headlight switch.  Basically, when this happens, the system is drawing too much current and tripping the internal circuit breaker inside the headlight switch itself.  Bad grounds, bad contacts, corrosion, etc. can all contribute to this issue.

I see too few 64.5's to understand the subtle differences between headlight switches.  Electrically, they seem the same...only the mounting is different.

[jwc66k]

Ford changed part numbers when they changed suppliers. This may be the case here, but the mounting requirements are the same: same location, same hole, same cable interconnect.
Jim

[MattDoscher]

The June 2010 issue of Mustang Monthly has a good article on these switches.  The article details the disassembly and cleaning of a switch and states that all switches are basically the same except for application and mounting bracket behind the dash.  The June 2011 issue also details switch replacement though not as detailed as the 2010 article.

Matt

[ajd350]

I have had this on/off problem with both of my 66's. One only does it on high beam so for. Does anyone know if the halogen bulbs draw more and could be an issue?

[midlife]

I have had this on/off problem with both of my 66's. One only does it on high beam so for. Does anyone know if the halogen bulbs draw more and could be an issue?

Bingo!  Halogens draw more current and have been known to cause the headlight switch circuit breaker to trip.  When using halogens, it is recommended to use relays and direct battery power.

[ChrisV289]

Not using halogens, using stock headlight bulbs....Guess I could change the dimmer switch on the floor since I know that is the original 46 year old part...Which BTW is Fomoco script and not block if anyone is keeping tabs on variations...

[ChrisV289]

OK so I changed the dimmer switch tonight and took it to a car show and had the headlights on and they seemed to work...Left the car show and was turning in the the neighborhood and the lights went on and off yet again....I'm totally lost now as to what it can be...It only stated doing this last year, not the other 18 years we have owned the car....Any thoughts as to what else it could be or what I should look for?  Keep in mind the headlight switch was changed about a year ago...