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Every once in awhile my headlights which are manual cut on by themselves. I don't know if they have a short or if maybe the switch is malfunctioning or what. I had noticed when using the headlights before this issue they almost flickered but not quite it was like they slightly dimmed and then came back to full power. I've had to have my car jumped twice because I didn't catch the lights being on in time. It's weird I guess I'm going to have to take it in and see what's wrong. Has anyone else had an issue like this?
 

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Every once in awhile my headlights which are manual cut on by themselves. I don't know if they have a short or if maybe the switch is malfunctioning or what. I had noticed when using the headlights before this issue they almost flickered but not quite it was like they slightly dimmed and then came back to full power. I've had to have my car jumped twice because I didn't catch the lights being on in time. It's weird I guess I'm going to have to take it in and see what's wrong. Has anyone else had an issue like this?
HL are turned on by grounding them. Per the diagram, the bulbs are "hot at all times" by separate fuses. Separate fuses are a fail safe design. Also since the two wires "HI & LO" go from the lights to the cabin to the MFS. If those wires fail and are grounded along the way, the fail mode is "lights on" rather than the older positive switching in which the fail mode is lights out.
-chart-
 

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Every once in awhile my headlights which are manual cut on by themselves. I don't know if they have a short or if maybe the switch is malfunctioning or what. I had noticed when using the headlights before this issue they almost flickered but not quite it was like they slightly dimmed and then came back to full power. I've had to have my car jumped twice because I didn't catch the lights being on in time. It's weird I guess I'm going to have to take it in and see what's wrong. Has anyone else had an issue like this?
You probably have either a Short or Hi Resistance in one or more wires. Use a multimeter to check battery voltage. That's your "System Voltage". Every wire you test should lose no more than 1 Volt. Check the grounds and power wires. Whartmaker gave you the diagram. Start testing circuits for VOLTS! Don't be concerned with continuity or resistance. You need to get system voltage to each light.
 

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You probably have either a Short or Hi Resistance in one or more wires. Use a multimeter to check battery voltage. That's your "System Voltage". Every wire you test should lose no more than 1 Volt. Check the grounds and power wires. Whartmaker gave you the diagram. Start testing circuits for VOLTS! Don't be concerned with continuity or resistance. You need to get system voltage to each light.
When doing any volt drop, remember the design. Note: #20 wire size from the MFS to the bulbs. Reason. Bat volts 13.8-14V. Bulb volts = 12.8. Life based on this volts. Wire size used to drop the volts approx 1.0V to 1.2V to save the bulbs. Bulb life -16^ of V/V over/under rated life. 5% in over volts cut life in half. Then, when one bulb burns out, the volts of it's mate jumps since they share the same wire.
Oh well such is auto stuff.
-chart-
 

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When doing any volt drop, remember the design. Note: #20 wire size from the MFS to the bulbs. Reason. Bat volts 13.8-14V. Bulb volts = 12.8. Life based on this volts. Wire size used to drop the volts approx 1.0V to 1.2V to save the bulbs. Bulb life -16^ of V/V over/under rated life. 5% in over volts cut life in half. Then, when one bulb burns out, the volts of it's mate jumps since they share the same wire.
Oh well such is auto stuff.
-chart-
Therefore, my "no more than 1 volt drop" is incorrect. To clarify, what would be a no more than "x" volt drop that would indicate faulty wiring for the headlights? What's your accepted volt drop for items requiring system voltage?

Thanks for the info.
 

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Therefore, my "no more than 1 volt drop" is incorrect. To clarify, what would be a no more than "x" volt drop that would indicate faulty wiring for the headlights? What's your accepted volt drop for items requiring system voltage?

Thanks for the info.
Approx 1.0V drop in either wire = HB or LB would happen with two incond bulbs standard watts size. Change that to some other bulb type and every thing changes. The wire from the fuse block to each bulb is so short to have very minor drop. If you want to get very specific, the pas side bulb has a slight lower volts if both bulbs are working. Longer wire path.
As for me, I use a relay and ground my low beams with local ground and they operate at near bat volts. Thus I expect ~1.5 years life of XP bulbs. And in aftermarket HL which bring my light output up much. Sable lamps ~$100 and easy retrofit.
-chart-
 

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While I have your attention. What's your opinion of replacing OEM headlights with HID? If approval, any suggestions - mfg etc. I've installed fog/running lights with relays, so I understand PWR to lights thru relay to switch & battery.
 

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I ran with HIDS for 10+ years in my '05 Sable without any problems, I recommend 5000k for a bulb temp.
You need to use 35w ballasts (not the 55w, the bulbs get too hot) and a relay harness, the Bi-Xenon work without any problems.
The only problem I ran into with my first harness years ago was that the socket was pinned backwards for the High/Low.
 
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