I seldom drive my 330GTC at night, but I did last week and my headlights were so dim as to be useless. I started checking voltage and found I only had 8.8 volts at the fuses. I appears that the fuses are feed from the toggle switch on the dash that turns on the lights, so I pulled the console and was able to get to the rear of the switch. I had 12.9 volts going to the switch. When I turned on the switch with the headlight switch on the steering column in the off position, I had 11.1 volts on one of the terminals (I think this was feeding the parking lights that were now on) and no voltage on any of the other terminals. When I turned on the low beams with the steering column switch I then had 8.8 volts at one of the terminals which had no voltage before. When I turned on the high beams I then had 8.8 volts on a different terminal that had previously had no voltage. I don't understand how there is no voltage to the terminals until a load is applied, but I guess that doesn't matter, the larger question is where is the voltage drop coming from. Any ideas?
Thanks for your help.
330GTC Dim Headlights
330GTC Dim Headlights
Regards, Terry Phillips 330GTC #9411
Re: 330GTC Dim Headlights
Hi Terry,
A simple test is to get some wire and bypass the switch to make sure the voltage drop is not inside the switch. These headlight switches often fail because they can't handle the amount of current the headlights draw. Jim Simpson at ODD parts can rebuild these switches. A relay can be added to the headlight circuit to cut down the amount of draw that goes through the switch once the switch is fixed. I have also installed LED headlights for my customers who want to drive their cars more than show them which cuts down the amount of current draw, and provides more light.
Good luck!
Tom
A simple test is to get some wire and bypass the switch to make sure the voltage drop is not inside the switch. These headlight switches often fail because they can't handle the amount of current the headlights draw. Jim Simpson at ODD parts can rebuild these switches. A relay can be added to the headlight circuit to cut down the amount of draw that goes through the switch once the switch is fixed. I have also installed LED headlights for my customers who want to drive their cars more than show them which cuts down the amount of current draw, and provides more light.
Good luck!
Tom
'63 330 America #5053
Re: 330GTC Dim Headlights
When you complete Toms suggestions, you may want to check the charging voltage at the battery; should be 14.4 or so with the engines little above idle. Then recheck the switch drop as suggested and at the lamp terminals. These will readily show the voltage drops and the corrections needed. Don't forget to check voltage drops at the fuse holder also major trouble area.