Please Help - Strange 12v relay issue - JeepForum.com
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post #1 of 9 Old 08-13-2020, 05:24 PM Thread Starter
turbogus
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Please Help - Strange 12v relay issue

I've wired up my other DD with relays as I've done with so many vehicles over the years including my '78 CJ5 'Black Betty'. The trouble that I'm having is with verified wiring to/from the Ford PDB I'm using is initially I have 12 output availablefor low beams. Then suddenly 3v down to 1.8v WTF? One headlight remains lighted and the other is extremely dim. Hi beams function correctly.
I've wired my headlights to the PDB with a junction for left and right low beams and a separate line for hi beams. All connections are twisted, soldered and seal in heat shrink tubing. I must have gone wrong somewhere but for the life of me, I can't seem to figure it out.

Thanks in advance for any help on this.

Gus


The parts shop that stocks part for Skylab II will not have parts for our year/model of Jeep
We cannot accurately judge the trajectory of a speeding critter (cat, dog, sasquatch)
Record heat waves and floods only occur when we visit that area
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post #2 of 9 Old 08-13-2020, 07:39 PM
4Low2G0
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Do voltage drop tests for the wire run, multi meter on DC volts, put one lead at connection with 12V
other lead following wire to headlight, meter should read 0 V if you get a large reading you have a
bad wire or connection. trace down the circuit at each connection to the headlight.

also verify ground for the offending lamp.

Whats over that next ridge?
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post #3 of 9 Old 08-13-2020, 08:34 PM Thread Starter
turbogus
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Thanks so much for your response, I think I follow, looking for a line break. As far as the ground goes I'll double check it but if the hi beam works I think the ground may be okay.

The parts shop that stocks part for Skylab II will not have parts for our year/model of Jeep
We cannot accurately judge the trajectory of a speeding critter (cat, dog, sasquatch)
Record heat waves and floods only occur when we visit that area
turbogus is offline  
 
post #4 of 9 Old 08-14-2020, 01:32 PM Thread Starter
turbogus
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After I went to bed I was thinking about this and it occurred to me that the headlights on This setup may be on a fused circuit. On 'Black Betty' they're using the same PDB.

The parts shop that stocks part for Skylab II will not have parts for our year/model of Jeep
We cannot accurately judge the trajectory of a speeding critter (cat, dog, sasquatch)
Record heat waves and floods only occur when we visit that area
turbogus is offline  
post #5 of 9 Old 08-14-2020, 04:28 PM Thread Starter
turbogus
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Okay grounds are solid and I found that one of the headlights had the wiring reversed for ground and hi beam. Also different wattages of H4. They are working now when switching from Lo to Hi beam there's no issue, but switching back from Hi to Lo beam and they don't reset to Lo unless I cycle the headlight switch.

The parts shop that stocks part for Skylab II will not have parts for our year/model of Jeep
We cannot accurately judge the trajectory of a speeding critter (cat, dog, sasquatch)
Record heat waves and floods only occur when we visit that area
turbogus is offline  
post #6 of 9 Old 08-14-2020, 11:50 PM Thread Starter
turbogus
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This is an approximate representation of the wiring;

The parts shop that stocks part for Skylab II will not have parts for our year/model of Jeep
We cannot accurately judge the trajectory of a speeding critter (cat, dog, sasquatch)
Record heat waves and floods only occur when we visit that area
turbogus is offline  
post #7 of 9 Old 08-15-2020, 04:45 PM Thread Starter
turbogus
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Even if I returned to the Flösser 140/90 H4's I note that I'm only pushing a little over 23 Amps which is well within the limits of the relays that I am using.

The parts shop that stocks part for Skylab II will not have parts for our year/model of Jeep
We cannot accurately judge the trajectory of a speeding critter (cat, dog, sasquatch)
Record heat waves and floods only occur when we visit that area
turbogus is offline  
post #8 of 9 Old 08-18-2020, 03:51 PM
4Low2G0
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you may need diodes in the grounds for the relays.

Whats over that next ridge?
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post #9 of 9 Old 08-18-2020, 07:54 PM Thread Starter
turbogus
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I did several diagnostics and despite help from here and elsewhere but to no avail. I just wired in the foot dimmer from 'Black Betty' and wha-la the low and high beam function properly so I'm purchasing another foot dimmer and I'm off to the races.
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The parts shop that stocks part for Skylab II will not have parts for our year/model of Jeep
We cannot accurately judge the trajectory of a speeding critter (cat, dog, sasquatch)
Record heat waves and floods only occur when we visit that area
turbogus is offline  
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