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Is the current load thru the multi function switch is reduced with LED bulbs in the DRLs, headlights and side markers? This switch is irreplaceable if it fails. Almost afraid to use the turn signals.
LEDs have a high resistance and there is less current. That is why you get hyper flash with LED turn signals. The current is so low, it thinks the bulb is blown.
You have that backwards. OEM incandescent bulbs use a lot more energy because it uses heat for light, in the form of resistance. The flasher is thermally driven and hyperflash is caused by current flow. Loss of resistance (LED or burnt bulb) causes too much current flow and the flasher heats too fast.
I'm with LWSZ06, LEDs use less current for the same amount of light output.. When you change a incandescent turn signal bulb with a LED, you have to install a resistor across the LED to increase the total current back to a "normal" value. The less current you pull thru the flasher, the faster it will blink. Like when the front burns out, the rear will blink faster.
Correct, Resistance goes UP and Current goes Down.
Also, the C5 doesn't have an old bi-metallic switch flasher. It is electronic and part of the Hazard Switch.
LEDs need increased resistance to stop hyperflash. AKA reduced circuit current stops hyper flash. AKA hyperflash is caused by too much current through the flasher circuit.
Wrong again, are you just a troll account? C5’s have bimetallic flashers; that is the exact reason why hyperflash happens at all. The hyperflash harness bypasses the OEM flasher with an electronic flasher to eliminate hyperflash.
To the OP’s point… LED turns with the bypass harness allows the circuit to operate normally except with increased current across the MFS, which is a common failure point and are no longer produced. In my experience, the turn signal contacts rarely fail but plenty of used units are available. Alternatively, a properly rated resistor would be enough to avoid premature wear.
Since I'm trolling, where is this bi-metallic flasher located? Why not just replace it instead of installing a hyper flash harness.
Here is a pic comparing an 3157 standard with a 3157 LED, check the wattage. The lower the wattage the lower the current, at the same voltage.
Yes, LEDs have low resistance and increase the current flow through the MFS. There are lots of spare switches on eBay.
Tony...you have it backwards. I happened to have just swapped out my incandescent DRL's last week with LED bulbs from Sharp Light Innovations. Before doing the swap I measured amp draw (current) with my ammeter and a spare car battery. The current draw is considerably less with the LED's vs stock incandescent.
Tony...you have it backwards. I happened to have just swapped out my incandescent DRL's last week with LED bulbs from Sharp Light Innovations. Before doing the swap I measured amp draw (current) with my ammeter and a spare car battery. The current draw is considerably less with the LED's vs stock incandescent.
Does that help reduce the load and wear thru the multi function switch?
Is the current load thru the multi function switch is reduced with LED bulbs in the DRLs, headlights and side markers? This switch is irreplaceable if it fails. Almost afraid to use the turn signals.
Depends.
If you install LEDs and a hyper flash harness, yes, you will reduce the load and wear on the MFS. If you install resistors across the LEDs to prevent hyper flash, then no, the load and wear would
be the same as original.
Also, installing LEDs on the front side markers reduce heat to protect the housings and the electrical connectors from damage.
Does that help reduce the load and wear thru the multi function switch?
Yes...it reduces current through the switch and wiring / connections in that circuit path. I put LED bulbs in my DRL's enclosures to reduce the heat load on the lens. But.....I'm not if the DRL path goes through the MFS. I'd have to look at my wiring diagrams. Some of the C5 electrical guru's like C5Diag or Bill Curlee could confirm for sure. Here's kind of a summary. I'm assuming that you are installing a hyperflash harness vs using load resistors.
Replace DRL's with LED bulbs. Note that these bulbs have 2 elements - bright element for DRL and Turn Signal functions, and low element for parking lights.
1. Lower current draw creates less heat when those bulbs are in DRL mode (no turn signals).
2. Lower current draw also happens with turn signal mode. The lower current draw makes the stock flasher think a bulb is burned out, hence the hyper flash.
3. Both of the above scenario's create less current flow - but I'm not sure if DRL mode also flows through the MFS.
The flasher is in the hazard button. The hyperflash harness is easier to install plus I am uncertain if anyone produces C5 hazard buttons with electronic flashers.
I think you are confusing current draw (the bulb) with current flow (the circuit.) Current flow is what every component in the circuit sees… flasher, MFS, wiring, etc. Imagine a dead short battery + to battery -. There is 0 resistance and infinite current flow (until fuse blows.) Imagine an open circuit, like an open switch… infinite resistance and 0 current flow. The current flow in the circuit is dependent on the resistance in the circuit. Reduced resistance from LEDs increases circuit current flow… they allow current to freely pass. Thus external resistors are added to the circuit to restrict current flow and return it to OEM specs.
The external resistor will protect the entire circuit (LEDs, MFS, wiring etc) from excessive current flow that it wasn’t designed for… which is introduced by switching to LEDs.
The flasher is in the hazard button. The hyperflash harness is easier to install plus I am uncertain if anyone produces C5 hazard buttons with electronic flashers.
I think you are confusing current draw (the bulb) with current flow (the circuit.) Current flow is what every component in the circuit sees… flasher, MFS, wiring, etc. Imagine a dead short battery + to battery -. There is 0 resistance and infinite current flow (until fuse blows.) Imagine an open circuit, like an open switch… infinite resistance and 0 current flow. The current flow in the circuit is dependent on the resistance in the circuit. Reduced resistance from LEDs increases circuit current flow… they allow current to freely pass. Thus external resistors are added to the circuit to restrict current flow and return it to OEM specs.
The external resistor will protect the entire circuit (LEDs, MFS, wiring etc) from excessive current flow that it wasn’t designed for… which is introduced by switching to LEDs.
Tony....we may just have to agree to disagree on this. Not sure if you were able to read the article I posted above, but the load resisters are installed in parallel with the LED bulbs to increase overall circuit current. In a series circuit (battery, flasher, bulb) the current is the same everywhere. Using Ohm's law, one can calculate the current. In that circuit when a LED is swapped in, less current flows. The flasher (non LED) needs to see more current to slow down the flash rate so a low ohm resistor is added in parallel to the LED. The load resistor increases current flow. In a parallel circuit total current is the sum of both parallel legs. Have you ever added a load resistor? They are large and get super hot due to the heat created by the extra current that they draw. You have to be careful where you install them so that things don't get too hot.
I did install LEDs thru out the entire car with the Hyperflash harness including the headlights. Everything works perfect just always worried about the headlight multi function switch. I know that they are on Ebay for around $500 used. Did read that the headlights would not close using LED bulbs. Mine function just fine with out the resistors. 2002 Vert.
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Is the current load thru the multi function switch is reduced with LED bulbs in the DRLs, headlights and side markers? This switch is irreplaceable if it fails. Almost afraid to use the turn signals.
Why do you say that the multi function switch is irreplaceable? GM no longer makes the switch but they are replaceable with a used one & or can be rebuilt. Redline sells them it looks like.
Why do you say that the multi function switch is irreplaceable? GM no longer makes the switch but they are replaceable with a used one & or can be rebuilt. Redline sells them it looks like.
Moreover, the aftermarket has made the occasional batch of replacement units, currently available from multiple sources, including SMP labeled pieces at Rock Auto. Not cheap, but not ludicrous either. Pick one up and put it on a shelf in the garage.
Multi function switch
