Why always Load Resistors? (1 Viewer)

This site may earn a commission from merchant affiliate
links, including eBay, Amazon, Skimlinks, and others.

Joined
Sep 20, 2011
Threads
4
Messages
36
Location
Australia
I run HID headlights on my cruiser, and am thinking about led indicators. One thing that has always bothered me is having to use load resistors to get hi/low to work or indicators to flash at the right rate.

Why does the circuit need this extra resistance? All it is doing is turning power into heat. Is it due to the resistance of the switch/relays not being truly infinite so enough current flows to trigger?

I've looked through the circuit diagrams, and tried searching but haven't found out the 'nuts and bolts' of why, just suggestions to fit load resistors to achieve the original load on the system. Is it a specific component that causes this behaviour?

Anyone know the electrical theory??
 
I have no electrical experience or valuable input but I do run HID's in my low beams and replaced all the other lights up front with LEDs. I have the rapid flash issue but I put that at the bottom of my list of priorities. If you do decide to install a resistor could you possible take a few pics of how/where you did it? Maybe I can finally knock this out. I took a look back there when I replaced all the bulbs and noticed there were 3 wires leading into the turn signal socket. Before I begin cutting and splicing I'd like to know which ones are the correct wires.
 
OK, so I think I understand the old-school flasher relays and why they speed up - lower resistance so higher current to the heater coil, hence quicker flash. I would have thought the 80 series would use a more modern relay?

Regardless, you can buy flasher relays specifically for LED's. Just require a separate earth, and they use a timer to control flash rate independent of load. I'll fit one up and post how if people are interested.
 
On the headlight circuit, I think the issues stem from the wiring design for the indicator bulb. Some drawings:
Low beam
ImageUploadedByTapatalk1430095767.424745.jpg


High beam
ImageUploadedByTapatalk1430095745.530251.jpg


Possible mod to get rid of load resistor
ImageUploadedByTapatalk1430095801.894614.jpg


I will experiment. If it doesn't work I'll come up with a buggery box that I can put somewhere easy to access.
 
Jeep guys typically use a digital or heavy duty flasher when they swap to flush mount tail lights. This way the flasher is not tripped by the resistance of the light. It flashes at the same rate no matter what. It might be possible to modify one of the Digital flashers for a Jeep to fit your Land Cruiser!

~Jeff
 

Users who are viewing this thread

Back
Top Bottom