Haltech PDM Tail light brake light and indicator combo

Hi,

im currently tuning a friend corvette and the issue is that the tail light on corvette have the brake lights and indicator combined.

i tried creating generic conditions to create a logic to turn off the brake light when indicator is on but I noticed the pdm act weird when I do that the brake light flickers so I assume since the brake switch is on the ecu side the flicker is from the can bus pulsing signal maybe, I tried adding delay for on and off it didn't solve it but there was some improvement.

anyway I wanted to ask is there a product in the market that can control the light or should I use two ways relay (indicator = on then on = indicator, off = brake light)

I have attached the logic I used, not sure if I should use or instead of and

See the post a couple of posts below.

Hi Gord,

i think XOR logic is not correct for brake light, if im understanding it correctly if both are on then there will be no output, I'm trying to have the indicator as always the priority I think the diagram below is better options but before I move to 5 way relay, is it possible to fix the flickering issues in PDM or is there a module that has this logic built into, I have been reading online that DRL module might be a solution but I don't think I understand how it works

Yes, with both brake AND indicator an XOR has no output, but remember the indicator is on/off in operation, so the light will be off/on if the brake is also applied - I went into more detail in the post. I don't know exactly what your options are using the PDM you have - which is? - it may not be an option, anyway.

I can't make out the details of the schematic, but even if I could, it's probably been way too many years to follow the operation.

ok this makes more sense but i would expect sync issue might happen between front and rear lights I haven't checked but we got it to work in haltech without external wiring.

I talked with fernando from haltech customer support and he helped me create the logic,

1. use 4 outputs for the indicators one for every corner otherwise it brake light would turn on the front lights.

2. assign the rear indicators to virtual output to create indicator state without output so you don't have any conflict in the software

3. create 2 generic output (one for Right / one for Left ) with 2x2 table one axis should be brake switch input and the other is (right / left) indicator state, using this table you will create the XOR logic, this way you will output both the brake light and (Right / Left) indicator on the same wire each side.

the brake light output is used only for the third brake light otherwise its not required.

now I need to figure out how to setup windows control using half bridge and how to park the output.

Doh, yes, I remember commenting on the need for splitting front (and repeaters) and rear. Me bad - the external option will be if you don't have the spare outs'.

Good to see you've got it sorted! :-)