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Discussion Starter #1
So driving with low beam light seems to be permanantly working. Once i switch to high beam they start blinking and finally totaly cut.

i tryed to change the relay with another used on, but problem was still there.

one thing to consider-relay was wery hot-??

seems like there is not enough power/ampere( alternator works)
 

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Sounds like either the high beam lamps are drawing too much current, or the wiring is defective or too small. Are the high beam lamps the correct ones, or an aftermarket high performance type? Does it look like the wiring has ever been replaced to the headlights?
 

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Discussion Starter #3
All wiring is repaired of a electronic-shop, splicing it from the original dimensions.

lamps are the ones ive used on all my cars for years- not HP
 

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I will bet that they used wire that is too large size. My 1993 Daytona uses only 20 AWG; previous Daytonas use 18 or 16 AWG. If they used too large a gauge wire, it will allow too much current to flow to the lamps, and the wiring will overheat, and trip a thermal circuit breaker, which resets when it cools. I will look at my 1984 factory manual, which is the same body style as 1986 and may be the same wiring.
 

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In 1984, low beam wiring was 16 AWG for the power and 20 AWG for the ground. The high beams were 16 AWG for power and 20 AWG for ground.
 

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What year car...?
 

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I think he has an 86.
 

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In theory I understand the concept that the heavier headlight wiring would cause less voltage drop and the corresponding increase in current flow to the load and in the circuit, but in reality I can't image that could be the issue for several reasons.
The difference in resistance between the two wire gauges isn't that much and it's hard to believe that the headlight circuit breaker is operated that close to it's maximum "hold" current rating that the one step up to the next heavier gauge twould push it over the rated limit enough to trip it. Normally going to a heavier gauge wire to feed the lights results in better lighting as the lights get operated closer to their rated voltage. 20 ga., or even 18 ga. is pretty light duty for the current draw of a headlight. Roughly between 4A and 5A per headlight assuming a 55 watt draw per. Two headlights, roughly 8 to 10 amps draw total at 12 volts, higher at charging voltage. Going to the lghter gauge in the later models was probably a bean counter move unless the newer headlight bulbs in the composite headlights had a lower wattage rating than the halogen sealed beams of the previous models. Another factor is that on the composite headlamped cars, the low beams estinguish when the high beams are turned on. On the earlier cars with the single pop up headlights did the low beam filament go out when the high beams were turned on ? On the quad headlamped cars the low beam lamp had a secondary high beam filament that lit with the high beams so it stands to reason that the earlier cars had to have a higher total current draw than the later models when in the high beam mode.

Could it be that the headlight circuit breaker is simply out of spec. due to aging ? Maybe the export headlight bulbs have a higher wattage rating than the OEM lamps and that's pushing it over the edge.
 

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I know this applies to 2nd gen cars, not sure if the 1st gen cars have these.......

But there are 2 diodes in the headlight circuit, one for each beam and for each light, so a total of 4. They are integral to the wires and can be found on the rear (engine) side of the radiator support. There is just a plug, and the wires forming a loop. I've had to replace several of these diodes - so they do blow out, I don't know what the spec is but I've just been using the biggest ones I can find at Radio Shack, they're rated for 6 amps, and have been holding up so far. Just unplug the wire, remove the loom and insulation, cut out the old diode and solder in the new one. As for the polarity, I've just been following the way the good one is installed, never had one where both diodes were bad, so always had the other one as a reference.





 

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george w said:
In theory I understand the concept that the heavier headlight wiring would cause less voltage drop and the corresponding increase in current flow to the load and in the circuit, but in reality I can't image that could be the issue for several reasons.
P = V2/R. That's the issue with going to larger gauge wire.
 

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Discussion Starter #11
thanks for answers guys- ive been away some days, but i will take up thread again - now i need to rest.
 
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