Indicator/Turn Signals - Argg!
Discussion
I finally headed out this morning to get my safety inspection (MOT-lite) and immediately had to turn back...no turn lights. I haven't had a problem with them and, other than replacing the battery yesterday, I haven't done anything electrical lately.
My thoughts:
The bulbs all work in hazard mode, so it's not a local ground/bad bulb problem.
Neither side works, so it's a common/shared problem.
The hazard relay is shared and I can hear/feel it click open/close in 'hazard on' mode.
All the other lights work properly (not sure about the instrument light today).
The turn signals worked yesterday.
All fuses in the main box are good.
I don't see a fuse downstream of the hazard switch so if the hazard works I think the turns would to???
That leads me to think it a problem to, from or at the turn switch.
Before I tear into the column, is there something simple that I'm missing? Thanks Grady
(1986 280i USA)
ETA - Took the connector at the column apart - appropriate continuity at the switch side. No power (ignition on) on the light green/black wire on the car side.
My thoughts:
The bulbs all work in hazard mode, so it's not a local ground/bad bulb problem.
Neither side works, so it's a common/shared problem.
The hazard relay is shared and I can hear/feel it click open/close in 'hazard on' mode.
All the other lights work properly (not sure about the instrument light today).
The turn signals worked yesterday.
All fuses in the main box are good.
I don't see a fuse downstream of the hazard switch so if the hazard works I think the turns would to???
That leads me to think it a problem to, from or at the turn switch.
Before I tear into the column, is there something simple that I'm missing? Thanks Grady
(1986 280i USA)
ETA - Took the connector at the column apart - appropriate continuity at the switch side. No power (ignition on) on the light green/black wire on the car side.
Edited by Grady on Saturday 8th April 19:27
When in the on position the hazard switch breaks the column switch indicator circuit, it could be as simple as dirty/faulty contacts in the hazard switch.
Switch LH or RH indicators on while putting a little pressure on the Hazard switch and moving it a little while in the off position
Switch LH or RH indicators on while putting a little pressure on the Hazard switch and moving it a little while in the off position
Update:
No sign of a separate flasher under the dash (either side). I took the binnacle apart (somewhat) to get the hazard which out and don't see one.
I took the connector for the horn and turn switch apart under the steering column, at the hazard switch and by the main relay station. No visible corrosion, sprayed with contact cleaner and made/broke the connections a couple of times each.
Tried holding/pressing the hazard switch. Nada. BTW- I replaced the old corroded switch a couple of years ago when it broke.
The 3 input pins on the hazard switch plug (car side) have power.
Can anyone confirm a separate relay and where it's located. Thanks Grady
No sign of a separate flasher under the dash (either side). I took the binnacle apart (somewhat) to get the hazard which out and don't see one.
I took the connector for the horn and turn switch apart under the steering column, at the hazard switch and by the main relay station. No visible corrosion, sprayed with contact cleaner and made/broke the connections a couple of times each.
Tried holding/pressing the hazard switch. Nada. BTW- I replaced the old corroded switch a couple of years ago when it broke.
The 3 input pins on the hazard switch plug (car side) have power.
Can anyone confirm a separate relay and where it's located. Thanks Grady
There is a separate indicator relay. On my 390 it's part of the relay board but on my 350i is was stuffed way back under the dash, above the pedal box. Mine played up a few months ago so had to track it down. I cleaned the connector/multiblock and it's now behaving all okay. it was a total pig to find though...
Hi Grady -
It sounds like your hazard switch has packed it up and died. It switches the power feed AND the hazard relay circuit at once. Hazards are powered while ignition is off, so you can leave a disabled vehicle with hazards on and take the ignition key with you. The indicators are powered through the ignition circuit. Inside the switch body is a small plastic rocker that breaks after growing brittle for 30 years (pictured). The switch then isn't sending power to the indicators while ignition is ON, but hazards work fine. I was going to make a rocker out of old circuit board material when Bill at Dominion found a switch with a good rocker for me. I reassembled the existing hazard switch and all was well.
It sounds like your hazard switch has packed it up and died. It switches the power feed AND the hazard relay circuit at once. Hazards are powered while ignition is off, so you can leave a disabled vehicle with hazards on and take the ignition key with you. The indicators are powered through the ignition circuit. Inside the switch body is a small plastic rocker that breaks after growing brittle for 30 years (pictured). The switch then isn't sending power to the indicators while ignition is ON, but hazards work fine. I was going to make a rocker out of old circuit board material when Bill at Dominion found a switch with a good rocker for me. I reassembled the existing hazard switch and all was well.
Here's the indicator/hazard circuit...
There's only one flasher for both hazard and indicator, If it works for either function, it's good. Same for bulbs etc. Spare your column further indignity and don't disassemble the indicator column switch as it will spray tiny springs and steel balls all over and will then resist reassembly.
There's only one flasher for both hazard and indicator, If it works for either function, it's good. Same for bulbs etc. Spare your column further indignity and don't disassemble the indicator column switch as it will spray tiny springs and steel balls all over and will then resist reassembly.
Hmmm... I think/hope I have a spare switch at home and will try that next weekend.
The hazards work.
The switch is new and not corroded but I think it has issues.
My hazard switch uses all 4 output pins (1-4)
5- not used
6- goes to the relay
7 - switched hot (signals)
8 - Always hot (hazards)
The only continuity in the switch is when it is ON and is between pins 6 and 8 - relay powered?
Nothing between 6-7 with the ignition on.
I would have thought there would be more continuity between the output pins and the powered pins but no.
I may have exceeded my own I/O level.
The hazards work.
The switch is new and not corroded but I think it has issues.
My hazard switch uses all 4 output pins (1-4)
5- not used
6- goes to the relay
7 - switched hot (signals)
8 - Always hot (hazards)
The only continuity in the switch is when it is ON and is between pins 6 and 8 - relay powered?
Nothing between 6-7 with the ignition on.
I would have thought there would be more continuity between the output pins and the powered pins but no.
I may have exceeded my own I/O level.
Edited by Grady on Sunday 9th April 17:59
Grady said:
Hmmm... I think/hope I have a spare switch at home and will try that next weekend.
The hazards work.
The switch is new and not corroded but I think it has issues.
My hazard switch uses all 4 output pins (1-4)
5- not used
6- goes to the relay
7 - switched hot (signals)
8 - Always hot (hazards)
The only continuity in the switch is when it is ON and is between pins 6 and 8 - relay powered?
Nothing between 6-7 with the ignition on.
I would have thought there would be more continuity between the output pins and the powered pins but no.
I may have exceeded my own I/O level.
Hey Grady,The hazards work.
The switch is new and not corroded but I think it has issues.
My hazard switch uses all 4 output pins (1-4)
5- not used
6- goes to the relay
7 - switched hot (signals)
8 - Always hot (hazards)
The only continuity in the switch is when it is ON and is between pins 6 and 8 - relay powered?
Nothing between 6-7 with the ignition on.
I would have thought there would be more continuity between the output pins and the powered pins but no.
I may have exceeded my own I/O level.
Edited by Grady on Sunday 9th April 17:59
Hoping you can follow this. I tried to be precise so if you read it carefully it doesn’t require you to intuitively remember that an Open switch will ‘closes off’ power in a circuit, etc…
We both probably jumped to bad assumptions when inspecting the circuit for the 1st time The pin labels in the Bible aren’t numbered with the same layout as they are on the back of the switch body. I’m using ONLY the switch body numbers, as I think you did in your post:
So:
Pin 6 isn't to a relay exactly, it's just a momentary flasher. It puts the 'flash' in for hazards and indicatiors...
Pin 7 and Pin 8 do trace back to relays, from the keyed Ignition circuit (7) and the always-on Auxillary Power from the battery (8)
Pins 1-4 aren’t all “Output Pins” in the sense that they switch all 4 corner hazards.
Instead:
Closing/connecting pins 1 to 3 switches power to the Left Hand light circuit.
Closing/connecting pins 2 to 4 switches power to the Right Hand light circuit.
They open/break and close/make in tandem to operate the four-way hazard function. The White Plastic rocker has a ‘H’ shaped copper contact piece for these connections. They are open/broken when in normal ‘run’ mode with “Hazards Off”
The other half of the switch body, Pins 5,6,7 & 8, sends power to the flasher unit from either the ignition circuit, or the battery circuit.
When the L & R Hazard paths (1-3 and 2-4) are open/broken , the power connection from battery to flasher across pins 6 to 8 is also open/broken - and the power connection from ignition to flasher across pins 6 to 7 is closed/made - both by the white rocker.
Pin 5 and Pin 6 are bridged together and are logically the same pin.
Although it’s not obvious, Pin 3 and Pin 4 are always connected together by the H shaped metallic part of the white rocker.
Pin 7 has 2 tabs over it. The outer/top tab is attached to the (Pin 8) battery circuit. The tab in between is connected to Pin 6 (flasher) and is bent so as to be connected to the outer tab (battery), unless pushed to connect to Pin 7 (ignition) instead.
There may also be a yellow wire coming from Pin 4 to an idiot light for the hazard circuit, as if seeing both LH and RH dash blinkers at once isn't meaningful. I'm not sure either of my old 280i had this.
After the flasher unit, the circuit forks; Power goes back to Pins 3 & 4, AND to the column switch (indicator lever), from where on things are more straightforward to interpret.
What happens when the white rocker breaks (like in my picture) is that the connection from ignition (pin 7, underneath both tabs) to flasher (pin 6, also the lower, sprung tab) is not closed/made when in normal run mode – but there may be enough of the plastic leg in place to still open/break the connection from battery (pin 8, or the outer/top tab) to flasher.
If you cannot get a suitable white plastic rocker, you can add a jumper from 6 to 7 to supply ignition current to the flasher. With ignition off, this ‘might’ then backfeed the ignition circuit (from the battery, through the hazard switch) when you activate the hazards and that could probably burn stuff up – so don’t do that for longer than it takes to get the car through your annual inspection.
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