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Negatively Switched Headlights
Posted: Sun Mar 05, 2006 7:47 pm
by RyanIAm
Few questions about wiring up a set of Nite Stalkers, using a TJM/4wd Megastores Loom. Just wondering if this will work:
It has the main relay, and from that comes fused Positive and Negative connections. It then has 2 wires which it says to splice into the two parrallel wires on the H4 Headlight plug, which are the High Beam wires. It then has another 2 wires for the switch, followed by the actual wires which go to the spotties.
Will this work with negatively switched headlights?
Posted: Sun Mar 05, 2006 9:06 pm
by -Scott-
Yes. Why wouldn't it?
Scott
Posted: Sun Mar 05, 2006 10:22 pm
by DamTriton
NJ SWB wrote:Yes. Why wouldn't it?
Scott
Because in a switched earth system, +12V is always on the headlight, and taking this back to the relay which is supposed to take
swithched 12 volts will mean the relay is always on. This would present a practical problem when looking for the right wire if the vehicle uses a combined globe, as in that case the "common" terminal on the globe would be connected to +12V, ie no seperate hi beam line. If you took the two switched lines from the headlight the relay would never be energised (open cct or earthed)
The solution would be to "flip" all the connections on the "control" side, using the +12 volts where the ground should be, and use the switched earth to ground (energise) the relay as needed. The power side of the relay should be ok assuming they havent put any Y joins in their loom for the relay control earth, and the relay power earth.
I don't know why they would need both high beam circuits though

Are you sure it isn't loom for a Hi/Lo beam setup?
Posted: Sun Mar 05, 2006 10:42 pm
by -Scott-
They're taking TWO wires to the headlight plug. There won't be 12V across the two wires until the high beams are switched on. So it doesn't matter whether the highbeam is negative switched or positive switched.
It's not really complicated.
Scott
Posted: Sun Mar 05, 2006 10:51 pm
by DamTriton
Dohhh!!!!
1/2A = RTFQ
I thought it was one wire to each headlight

Posted: Mon Mar 06, 2006 9:34 am
by RyanIAm
Thanks for the replies guys, seems straightforward enough now
