Hazard & Defroster -- Rewire to Toggle Switch

[Digitalwave]

My track car has a deleted HVAC panel that I have set up with 30a toggle switches for various functions. Instead of mounting the stock defroster and hazard switches on that panel, I would like to keep it cleaner and wire them both to toggle switches. Being as though the defroster is fused @ 30a, and the hazard at 15a, I think I am going to use a relay for both of them.

The defroster switch seems like a pretty similar in/out design.

However, the hazard is a little more complex. I don't care if my toggle switch flashes in any way shape or form. The thing that confuses me is that the hazard has both a constant 12v AND a switched 12v input. The constant 12v makes sense since the hazards will work without the key in the ignition. However, why would you also need/want a switch 12v input to the hazards as well? There is only one output wire. Will the switch still work if I use either/or the constant or switched power?

Here is a link to the ETM: http://wedophones.com/Manuals/BMW/19...g%20Manual.pdf

The defroster is on page 62. My plan would be to cut the 2.5 gn/bu input power and make that the powered feed on the relay. Then cut the 2.5 bk and make the output of the relay. The toggle switch would be powered by simple 12v switched and would be the trigger for the relay.

The hazard is on page 76. As you can see it has both a 1.5 vi/gy switched 12v (fuse 4) and 1.5 rd/wt (fuse 24) input. The output is only one wire, the 1.5 gn/vi that goes to the flasher module. If I wired only the switched 12v to the input of a relay, would the hazards still flash? They both seem to be on the same switch.

The input switch is tied to several other switches for the illumination. Would any of those cause an issue with the flashers functioning when I bypass the base?

I only have a basic understanding of electrical diagrams. Any insight would be appreciated! Here is a pic of my interior and switch panel for attention.

[Das Delfin]

I just inadvertently closed the window so I'll try a better explanation this time..

The switch has input from fuse 4 for the turn signals and fuse 24 for the hazards. The hazard switched is designed in such a way to make use of only one flasher relay for both the turn signals and hazards. There are 5 internal switches inside the hazard switch that all switch on or off together and direct power based on input from the turn signals or hazard switch. Because of the way it's designed you'd have to design something complicated to make it do what you want to do (if you want to retain both turn signals and hazards).

The signal path is as follows: For the hazard function, power comes in from fuse 24 via the rd/wt wire. When the hazard switch is ON, the signal is sent out along the gn/vi wire to the flasher relay. After this the signal comes back in to the hazard switch, but to a different internal switch, where it is distributed along the bu/bk and bu/rd wires to the right and left turn signals respectively. (The signal also goes through a microswitch so that the switch will light up and flash along with the flasher signal, though that part isn't as important to you.)

The turn signals' power is routed through the hazard switch (again to make use of a single flasher relay) so if you got rid of the hazard switch, you'd also have to make up something so your turns would work again.

Because of the complexity of the switch, your best bet is going to be to keep the hazard switch.. move it over next to the headlight switch in place of your fog light switch

[Digitalwave]

Damn, that probably saved me hours of headache. Thank you! I do want to keep both the turn signals and the hazards functional, as even though it's a dedicated track car, it still gets driven on the street occasionally. So this one is probably better left as-is.

I don't have fog lights so that would be perfect to relocate the hazard switch to where the fog light button was. Thank you for that idea!

Do you think the defroster switch is more simple and can be executed with a relay and toggle switch?

[Das Delfin]

Yes, it looks like you can use a toggle in place of your stock defrost switch just by placing it in between the gn/bu and bk wires (if you don't care about illumination when on)

[Digitalwave]

Yes, it looks like you can use a toggle in place of your stock defrost switch just by placing it in between the gn/bu and bk wires (if you don't care about illumination when on)

I would be able to get illumination of the LED toggle switch to know it's on at least. Thanks again for your help! I will update the thread with the results once I rewire the defroster switch.

[jeffnhiscars]

I just inadvertently closed the window so I'll try a better explanation this time..

The switch has input from fuse 4 for the turn signals and fuse 24 for the hazards. The hazard switched is designed in such a way to make use of only one flasher relay for both the turn signals and hazards. There are 5 internal switches inside the hazard switch that all switch on or off together and direct power based on input from the turn signals or hazard switch. Because of the way it's designed you'd have to design something complicated to make it do what you want to do (if you want to retain both turn signals and hazards).

The signal path is as follows: For the hazard function, power comes in from fuse 24 via the rd/wt wire. When the hazard switch is ON, the signal is sent out along the gn/vi wire to the flasher relay. After this the signal comes back in to the hazard switch, but to a different internal switch, where it is distributed along the bu/bk and bu/rd wires to the right and left turn signals respectively. (The signal also goes through a microswitch so that the switch will light up and flash along with the flasher signal, though that part isn't as important to you.)

The turn signals' power is routed through the hazard switch (again to make use of a single flasher relay) so if you got rid of the hazard switch, you'd also have to make up something so your turns would work again.

Because of the complexity of the switch, your best bet is going to be to keep the hazard switch.. move it over next to the headlight switch in place of your fog light switch

That you took the time to figure this out is such an e30 owner type thing.

I love it :)

[Digitalwave]

So yesterday I was going to move the hazards to the window switch and just be done with it. However, as soon as I plugged in my hazard light switch I realized I had an electrical issue. When the key was off/out, turning on the hazards also turned on my cluster, power to the window switches, and turned on my gauges. When the key was switched on, it all worked normally.

I spent hours trying to figure it out. I did everything from testing all fuses, to removing and testing every relay in the engine bay and under the dash. I also tried multiple hazard switches, multiple headlight switches, removing all switches, tracing the splices I had made under the dash, etc.

It seems like the issue is with fuse 24 and/or the K7 unloader. I tried different relays on the K7 and nothing seemed to work. Fuse 24 is only for the constant power to the hazard lights. Pulling fuse 24 would obviously stop the issue, but also keeps the hazards from working with the key off.

The only other thing I could think of is that it had something to do with the switched power from fuse 4 (grey/violet wire). I had snipped out the glove box light and glove box switch, which runs on the same circuit. I don't know if that could be related in any way.

The other curious thing I found is that my grey/violet wire had an OEM splice close to the base of the hazard switch. I could not find that splice anywhere in the ETM. I don't remember what it was originally for. I had been using it as a switched 12v trigger wire for my electric fan relay. With the key off and the hazards on, that grey/violet wire which is supposed to be switched 12v was getting power. Last ditch idea is that there is a short inside the switch, bridging the switched grey/violet with the always hot red/white wire. But having tried two switches, it seems unlikely that both would have the same issue.

It drives me nuts that I couldn't find the issue, but I had to move on. I spent a good 5 hours trying to figure it out. For now I have pulled fuse 24, so the hazards don't work with the key out. I didn't want to risk a power drain when the car is off. Other than that I couldn't find any other issues or problems. Maybe I'll come back to this down the road.

[Das Delfin]

With fuse 24 pulled your hazards shouldn't work at all..

Your vi/gray wire is the power feed for the turn signals. Its splice should be a rd/green wire according to the ETM. Either way this is separate from the hazard circuit so shouldn't be the cause of your issue.

It's like when the hazard switch is on it makes the car think the key is in RUN. You could check for continuity between the rd/white and violet/gray

Maybe something stupid like the switch is in upside down? Not sure if that's possible though

edit - there was a top gear where they showed that turning the hazard switch put the car in RUN mode. The car was some old subcompact fiat