# no low beam on gto 65



## ERIC60 (May 14, 2017)

i have an issue I discover now by chance: when I pull the light switch full way, I toggle between full lights (high and low beam) or nothing when I press the foot switch;
I tried to investigate but the foot switch is not really accessible from underneath and the light switch either; (dashboard must be removed)
any idea will be welcome!!:frown3:


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## BLK69JUDGE (Jun 10, 2010)

*an idea*

my money is on a dimmer switch failure

very common ..... very common for the wiring at the floor dimmer switch to arc and get hot also ....

pull up the carpet and check it out ... unbolt the switch from the floor...

unplug the plug ....one wire in is hot ..with the switch on ... jump from the hot
to one of the other spades ... do your lights com on > jump to the other .. lites on?

jump to both all 4 should be on ..

Scott


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## ERIC60 (May 14, 2017)

thanks for tip!
I did not dare to unbolt the switch from interior of the car, fearing that the switch falls in the outer part of the floor;
I thought that wires would not be accessibles from inside, but only on motor side, which is impossible to reach without dismantling a lot of bits;
so I'll try this... and let you know


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## ERIC60 (May 14, 2017)

dimmer switch is fine ; ( tested with ohm meter) I guess the problem is further on the bulkhead connector;
is it located behind the fuse box???
I can't see it from inside the car;
I tried to pull out the fuse box in order to watch behind but it resists when I pull and I scare to disconnect wires!!
help!!


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## PontiacJim (Dec 29, 2012)

First, I have to ask the "silly" questions.

Did you check the fuse? Test each side of the fuse to ensure it is supplying power through it when you pull on the headlight switch. I have had fuses that look perfectly good only to have them blown out inside/under the metal ends that snap into the fuse holder and you could not see it. But, I assume the fuse is working if you have power to your dimmer switch.

Did you pull out the headlights that are not working and test them by applying 12 volts from a jumper wire off your battery? I would first want to know that the headlights actually work before digging into wiring.

Next, did you use a test light to see if you had 12 volts at the plugs that plug into the back of the headlights? I would want to know if there was any power at all coming off any of the plugs.

Next, check for grounding. If you do not have a good ground, the lights will not work - assuming that the headlights do work and that you have 12 volts at the plugs that go into the headlights.

If the headlights do work with a test lead, and you know you have a good ground, and you do not have 12 volts at the plugs, THEN you want to trace your wiring back to the firewall. You want to do a continuity test using an OHM meter to make sure that you do not have a broken/cut or grounded power wire. I would do the front wiring first, firewall forward, before tackling anything that might be dash related.

If you are getting power to the dimmer switch, each plug reacting as it should to 12 volts as you step on it each time to change high/low beams, then your headlight switch is working - so no need to mess with it. If power is coming off the high/low beam floor switch, then it to is working. Your fuse should also be good.

I have never had a problem with a fuse block, it has typically been wiring on one side or the other of the fuse block. I am not sure how yours pulls apart. I recall my '68 fuse block has 2 bolts/screws on the inside that need to be removed and one bolt on the firewall side in the engine compartment. I assume that yours may be similar. You might just need a little light to see them clearly. Once the bolts are out, they should pull apart. But again, I would not do this until I was certain I had to do it.


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## ERIC60 (May 14, 2017)

Hi Jim,
I think , due to my poor english, I explained badly my issue or you missunderstood something;
when I toggle the dimmer switch, with light switch fully pulled, I have in one position full light (high+low) and all off in the other position;
which means that fuse and bulbs are ok; I checked continuity from bulbs to bulkhead connector on motor side which is ok too;
that's why I'm convinced I loose my continuity between dimmer switch and bulkhead connector inside the car;
so I'm back to my question: where can I see the bulkhead connector on the car side? is it behind the fuse box?
I guess it shoul be easy to find, but since I don't find it, I suppose it's hidden by something else;


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## 64GTOConvertible (Aug 28, 2016)

Bulkhead connector is the back of the fuse box. You can see 2 wire harnesses coming out of the firewall. These are a bit tough to get apart, but you can do it with some work. I'm thinking this isn't where the problem is, though.

Good luck!


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## ERIC60 (May 14, 2017)

yeah!
I found my problem:
it was a lost of contact in the bulkhead connector; after uncliping to check continuity which was ok, I notice a lot o grease inside (conductive grease?)
anyway, I sprayed a contact cleaner from Loctite and now everything is fine ! whew!


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## 64GTOConvertible (Aug 28, 2016)

Yeah, the grease prevents corrosion. Glad you found your problem!


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