- #1
phlegmy
- 120
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hey guys, i could as easily post this in an automotive type forum but I'm not a member of any! no specific car knowledge nescessary!
Here is the problem
Where I'm working now, there are two jeeps and one Car type trailer
jeep 1 operates all the lights on the trailer successfully
jeep 2 will only operate the indicators, no other trailer lights function at all
i was given the task of investigating why jeep 2 will not power all lights (side lights brake lights etc)
i have determined the trailer and jeep1 are wired correctly
to determine if jeep 2 is wired conventionally i used a multimeter while getting someone to turn on various indicators, lights etc
all terminals on the socket produced a voltage when they should, so i reasoned it was wired correctly
now here's the situation:
i connect the voltmeter across the grnd and tail lights on the lights socket on the jeep with the trailer lights plugged OUT.
with the jeep lights on, this shows a few volts (cant remeber how many maybe 8-11v) as i'd expect
now i plug in the trailer lights, the voltage drops to ZERO!
so i think, hmmm what could be causing this?
could it be that the wire is grounded or shrt ccted furter up on the jeep end... but i figured that if it were, i would not read such a high voltage with the trailer plugged out as 99% of the voltage would drop across the short?
so secondly i considered that there is some kind of high resistance somewhere along the positive supply, i.e. a high resistance in series
so i'd have battery+, high reistance, bulb, battery-
i figure that this high reistance in series wouldn't affect the voltage I'm reading across the terminals. but when the cct is closed (i.e. i plug in my trailer lights) 99% of my voltage drops across the big resistance fault, leaving only a few mV across my bulb, or even ZERO.
IS MY THINKING CORRECT and if so does anyone know how such a big resistance can suddenly appear (the jeep did function with trailer lights previously I'm told) or is there another type of fault that could cause this to happen.
in any case thanks for reading and i'd be interested to read any replies!
james
Here is the problem
Where I'm working now, there are two jeeps and one Car type trailer
jeep 1 operates all the lights on the trailer successfully
jeep 2 will only operate the indicators, no other trailer lights function at all
i was given the task of investigating why jeep 2 will not power all lights (side lights brake lights etc)
i have determined the trailer and jeep1 are wired correctly
to determine if jeep 2 is wired conventionally i used a multimeter while getting someone to turn on various indicators, lights etc
all terminals on the socket produced a voltage when they should, so i reasoned it was wired correctly
now here's the situation:
i connect the voltmeter across the grnd and tail lights on the lights socket on the jeep with the trailer lights plugged OUT.
with the jeep lights on, this shows a few volts (cant remeber how many maybe 8-11v) as i'd expect
now i plug in the trailer lights, the voltage drops to ZERO!
so i think, hmmm what could be causing this?
could it be that the wire is grounded or shrt ccted furter up on the jeep end... but i figured that if it were, i would not read such a high voltage with the trailer plugged out as 99% of the voltage would drop across the short?
so secondly i considered that there is some kind of high resistance somewhere along the positive supply, i.e. a high resistance in series
so i'd have battery+, high reistance, bulb, battery-
i figure that this high reistance in series wouldn't affect the voltage I'm reading across the terminals. but when the cct is closed (i.e. i plug in my trailer lights) 99% of my voltage drops across the big resistance fault, leaving only a few mV across my bulb, or even ZERO.
IS MY THINKING CORRECT and if so does anyone know how such a big resistance can suddenly appear (the jeep did function with trailer lights previously I'm told) or is there another type of fault that could cause this to happen.
in any case thanks for reading and i'd be interested to read any replies!
james