Headlight Relays Part 2
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Intermediate
Joined: Aug 2023
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From: Virginia
Headlight Relays Part 2
The reason I was installing relays in the first place was because the thermal relay would kick out after a couple of seconds of turning on my headlights. This was a new switch that I had installed after the vacuum part of my old switch failed. I don’t know if the thermal cut out on the old switch or not (I just replaced it shortly after buying the car due to the vacuum issue and never used the headlights). Before installing the relays, I was checking everything and turned on the switch after cutting the wires (no power going to the actual headlights). The thermal still cuts out with no load from the headlights. I also disconnected the dimmer switch and the switch still cuts out after a couple of seconds. Do I have a bad replacement switch or is there something else I should check first? Thanks.
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The thermo as you are referring to is a circuit breaker. Most circuit breakers are thermo in design.
so, determine which wire is the wire that goes from the headlight switch to the high/low switch. Which you have already disconnected and the breaker still blows.
This wire, don't know the color as I have no idea what year car you have. Put an ohm meter on it and to a good ground. Should be 0 ohms. If you get a reading. The wire from the headlight switch to the dimmer switch is shorted to ground and that would explain the breaker popping. If indeed the wire tests out 0 ohms to ground there is no short and the aftermarket market switch is junk like most of them.
so, determine which wire is the wire that goes from the headlight switch to the high/low switch. Which you have already disconnected and the breaker still blows.
This wire, don't know the color as I have no idea what year car you have. Put an ohm meter on it and to a good ground. Should be 0 ohms. If you get a reading. The wire from the headlight switch to the dimmer switch is shorted to ground and that would explain the breaker popping. If indeed the wire tests out 0 ohms to ground there is no short and the aftermarket market switch is junk like most of them.
Racer
Joined: Oct 2018
Posts: 457
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From: England
The thermo as you are referring to is a circuit breaker. Most circuit breakers are thermo in design.
so, determine which wire is the wire that goes from the headlight switch to the high/low switch. Which you have already disconnected and the breaker still blows.
This wire, don't know the color as I have no idea what year car you have. Put an ohm meter on it and to a good ground. Should be 0 ohms. If you get a reading. The wire from the headlight switch to the dimmer switch is shorted to ground and that would explain the breaker popping. If indeed the wire tests out 0 ohms to ground there is no short and the aftermarket market switch is junk like most of them.
so, determine which wire is the wire that goes from the headlight switch to the high/low switch. Which you have already disconnected and the breaker still blows.
This wire, don't know the color as I have no idea what year car you have. Put an ohm meter on it and to a good ground. Should be 0 ohms. If you get a reading. The wire from the headlight switch to the dimmer switch is shorted to ground and that would explain the breaker popping. If indeed the wire tests out 0 ohms to ground there is no short and the aftermarket market switch is junk like most of them.
Race Director
Joined: Nov 2006
Posts: 13,229
Likes: 7,825
From: Sunshine Coast, Queensland, Australia
2025 C3 of the Year Finalist - Modified
2024 C3 of the Year Finalist- Modified
2022 C3 of the Year Finalist - Modified
Cruise-In VIII Veteran
