31 replies to this topic

[roblightbody]

Hazard light switch is one of the things I regularly "exercise" in my Mini - the switch seems to just stops working if not used for a while, or does strange things.

[lildeucecoop72]

Have you checked the earth wire on it or the flasher relay?

[cal844]

Hazard switch and interior light not working is the inline fuse on the Purple/orange wire behind the carb.

[Richard_]

I'll be interested to see replies to this. I've got an '89 racing green with non-operating hazards. It's an mot fail item.

[sonscar]

Five minutes with a wiring diagram and a power probe would probably unearth the mystery?Steve..autocorrect

Edited by sonscar, 18 May 2022 - 09:48 PM.

[Digikiller84]

Update since I haven't been near the car since I last posted, I removed and tested the inline fuse on bulkhead (wired BR/PO) and tested for continuity and resistance, seems fine, used some emery paper to clean up both terminals and refitted, no joy. Turned on one indicator and when depressing the hazard warning switch, the bulb in the switch illuminated as it should but when switch completes the 'flip' to fully on, indicator and hazard bulb in switch both stop. Going to try clean the switch. Will keep updated.

[Digikiller84]

Update to the update and this is pretty bizarre....so I pulled the hazard switch and disassembled it to clean it, contacts looked pretty decent so just used some emery on the slider and reassembled...problem persists but in my thickness turning the indicator back to the middle, I switched it to the other side and BOOM...hazards working...what the hell is going on lol?! So to clarify the settings:

Hazard switch fully on and indicators off = no hazards or hazard switch bulb
Hazard switch half on and indicators off = no hazards or hazard switch bulb
Hazard switch half on and left indicator on = hazard switch bulb flashes but still only left indicators flash
Hazard switch and right indicator on = hazard switch bulb and exterior hazards working.

(Update: hazard switch bulb now no longer works in any scenario...) steadily losing my mind lol

[sonscar]

As I have said,look at the wiring diagram.The hazard switch does two things,firstly it disconnects the indicators.Second it supplies an interrupted live from the hazard flash can to all the indicators.It is very simple.
You have connected the plug the correct way up?Put away your multimeter and fashion a bulbholder with two flying leads earth one lead and look for the live with the other which should light the lamp.Sometimes on elderly electrics on cars a multimeter can show good which then fails under load.So you have a permanent live, a fuse, a flasher can, a switch and four lamps.How hard can it be.??Have fun,Steve..

[Digikiller84]

Yeah so as it turns out, there seems to be a break in the PU/O wiring after the inline fuse and before the flasher unit. So gonna rewire direct to the constant live with a fuse to the flasher and worry about the interior light another day. Forgot to mention that I needed the ignition on for any hazard light scenario to work. There is also a loose constant live at the relay box so I will address that first but I don't think that's my problem as it only came off later in the troubleshooting, but stranger things have happened I suppose. Thanks for the tip though.

[Digikiller84]

Another thing I should mention is that my car is built here in Belgium and the wiring, especially at the fuse box (i said relay box before but meant fuse box), is different from the Haynes manual. I have 2 brown wires opposite a purple, whereas the Haynes manual says I have 2 purples opposite a single brown, and all of the wires going to the fuse box are on opposite sides to the Haynes manual except those on 1 and 3, green and white solid cables I believe.

[sonscar]

Hazards should function with the ignition off,ie un switched live,Steve..

[Ethel]

It's fairly simple once you've got your head round it.

 

The hazard switch has a pair of terminals on the  bottom which connect the flasher unit to the indicator stalk. When you flick the switch those terminals are disconnected to stop the indicators working while it connects all of the other 4 pins( in a square) to operate the hazards.

 

That's one pin for supply from the hazard flasher; one pin that powers the bulb inside the switch (small loop of wire to a spade terminal on the switch's side);

one pin for each side of indicator bulbs - so they can be isolated from each other when the hazards are off & the indicators selectable.

 

Armed with that info & a bit of wire, or a paperclip, for a jumper. You can connect your known working supply (light green/brown) indicator supply (ignition on) to each & all the outlets on the hazard switch connector block. If all those check out connect the feed for the hazards (purple/orange) instead and you should have a good idea if the switch is faulty, or which wire(s) you need to trace along to find the fault.

[sonscar]

It is simple for you and I because we know/can work out how it works.For others the very simple Mini electrics may as well be on a space shuttle.At the most basic the electric leaves the battery through a fuse,through a switch,through the gizmo and back to the battery.Armed with this knowledge it should be possible to fix most things,Modern cars are much more complex,Steve..

[Digikiller84]

Electrics and especially wiring diagrams are not my strong suit for sure, however I did get the hazards working again (but not my interior light) by means of placing a wire from the PU/O terminal on the flasher unit to the inline fuse. I'm 90% convinced it's a break in that PU/O wire somewhere after the inline fuse and before the flasher but the cabling layout is confusing me. For example, I imagined the cable would come from the inline fuse and direct to the flasher, with maybe a split to interior light but it seems to loop back after the fuse and into the loom in the opposite direction, and from the flasher the same thing, the flasher unit doesn't look directly attached to the inline fuse. I'll take a picture tomorrow. And the other thing that's bothering me is the second brown wire that came loose from its connector on the same fuse in the fuse box as the constant live doesn't seem to affect any of the things the wiring diagram says it's for...if been staring at this diagram for days now lol

[Ethel]

Just had a gander at what I think is the correct wiring diagram. The inline fuse is fed from the starter solenoid (brown wire) that's spliced in to a fair few other circuits:

 

Supply for the starter relay (brown terminal 30)

 

Auxiliary cooling fan (another line fuse)

 

Fusebox fuse for brake test, horn etc. (brown before the fuse, 2 purple wires after the fuse)

 

If any of those work you'll have narrowed it down a bit. 

 

I'd try & identify the likely candidate on the starter solenoid and follow it up. If they're all crimped in at the same place it'll make a bit of a bulge in the loom.