Steering column switch problem

[CJHenderson]

After I finished installing all of my instruments and tightening the steering column, I did a check on my turn signal found it not working. Followed the steering column ohm check for the connector, everything checked out. My question is, since I have confirmed that the plug for the steering column is wired correctly, is it possible that the new wiring harness plug is not wired properly?

[Leester]

If you scroll down on this link, you will see the electrical connectors (M & F) under the dash for the multifunction switch. You could try disconnecting the multifunction switch and just put 12 volts to the terminals for the turn signals and see if they light. There may be better ways to do this but that would be my first try - assuming of course that your fuses and bulbs are good.

https://www.sl113.org/wiki/Electrical/SteeringColumnSwitch       good luck,  Lee

[CJHenderson]

The turn signal is dead, jumped from battery to pin 10 no luck, hazard lights confirmed that the lights work. Next thing I'm going to try is flushing out the block itself with electronic cleaner hoping that cleaning it will make the contacts connect. If not, it will be a chunk of money with no guarantee.

[rwmastel]

If not, it will be a chunk of money with no guarantee.

There must be testing to determine the problem. 

[Leester]

Trying to clean the switch is worth the effort but if that doesn't work out Bob H posted this earlier:  Hello, Sead refurbishes these switches,

it's worth messaging him to see if he can help      https://www.sl113.org/forums/index.php?topic=37935.msg277479#msg277479

Not cheap and even worse now with tariffs.

Sead did mine and it works perfectly.

[Pawel66]

Have you checked the switch with multimeter for continuity? This is the simplest test to see if the issue is with switch or with wiring.

Did you mention new harness? Or new plug?

Is your turn signal wiring with hazard switch and the flasher relay or just with hazard switch?

If the switch worked before, then you worked on harness or plugs - that is where I would look for culprits.

[CJHenderson]

Yes, I've done it twice using the steering column switch instruction, both times checked good on the ohm meter. going to dismantle the block and clean and dry the contacts. I have backed off the 4 screws enough to see the spring's location.

[CJHenderson]

The turn signal was very dirty, cleaned it out and reassembled still does not work, everything else checked good, such as the windshield wipers, and washer.

[BobH]

As Pawel alluded to, if the indicators all work with the hazard switch, it's likely that that's where the problem is, can you let us know what type of hazard switch you have and whether it also controls the indicators, or if you still have the original "blinker" relay.  Do you have the small harness between the hazard switch and 12 way column switch connector?

[CJHenderson]

Well, I can tell you it isn't Bosch it is looking like an OEM that came with the car. I still have the blinker relay; it has no difference when plugged in or unplugged. Yes, it is still attached to the harness.

[BobH]

I think i would try unplugging the harness to the hazard switch, and restore the 12 way connector and original harness to how it was, leave the original blinker relay in place and see if they work then

If they do then we need to see why the hazard switch is affecting them

[CJHenderson]

I was hoping not to hear that, oh well since I have a Bosch hazard switch in my box somewhere I will pull out the dashboard instruments and give that a shot.

[BobH]

i don't think you need to do that yet, just unplug the harness from the 12 way connector below the dash and restore the harness back to original, without the short harness in circuit, as if the hazard switch wasn't fitted.  No need to touch the hazard switch until you can prove that's the problem

[CJHenderson]

I have it unplugged and nothing has changed, though there is another 6-pin plug that looks to be for the Bosch unit that came with the new harness

[BobH]

You could try linking between wires in the column switch, be careful, as it will be live, perhaps disconnect the battery, pull it out slightly from the column, enough to access the connections

With ignition on, link

Black/White/Green to Black/Green
black/White/Green to Black/White

If still no luck, try linking the same pins/colours in the female side of 12 way connector

Of course, you may just have a failed blinker/indicator relay

Just another thought, you haven't changed your filament bulbs for LED's have you?

[CJHenderson]

I don't think I want to cross wires but replacing the flasher unit would be cheaper than a whole new wire harness. I have a flasher that I thought was a Bosch that I got from SLS but looks like it's a copy of a Bosch. Otherwards after market. I'll order a flasher if I can find one if that don't work then I install this SLS switch

[Pawel66]

Please note that if your harness effectively provides wiring like we have on the 280SL diagram in the Tech Manual, then:
1. The flasher relay is not connected, it does not work anymore as if it was not there
2. You have to have hazard switch plugged as blinkers will not work without it

Again, the critical test of steering column switch is to check continuity with multimeter between wires coming out of the steering column switch:
1. Between black/white/green wire and black/green wire, there should be continuity when switch is in turn right position
2. Between black/white/green wire and black/white wire, there should be continuity when switch is in turn left position

If there is no contniuity, the switch is shot. If there is continuity, the fault is somewhere else.

[BobH]

Linking across the pins in the column switch will just simulate the turn signal switch, left and right

What is confusing is that your car, depending on the VIN should not need the sub harness between the hazard switch and 12 way connector, of your VIN is 12089 or later, then this was dispensed with, and the main harness then fed the hazard switch and the separate blinker relay was redundant.  The fact you're still using the sub harness indicates that you still need the separate relay.  You say you have another 6 way plug as part of the main harness, perhaps that needs to be plugged into the correct Bosch hazard switch for hazards and turn signals to work and the sub harness dispensed with

[CJHenderson]

I have done two continuity tests, which checked good according to the multifunction instructions. Since that checked good, I opened the female half of the plug, the number 3 pin is supposed to be black/white/green, but the color is black/white/yellow. Another thing I removed the "Y" harness you will see that there is a 6-pin plug which I think is for the Bosch switch. If I'm correct then I have two plugs which does the same job.

[lpeterssen]

Dear Mr Henderson

I think I already told you before, that this loop harness for hazard relay circuitry was REDUNDANT in your particular new wiring harness you bought from SLSHOP.COM.  Your new SLS harness has already the connection (6pin connector) for an early version hazard relay.

You may consider that if the hazard function is active/functional then problem is related only to a defective hazard/flasher relay.  You may try disconnecting the hazard/flasher early style relay (rectangle unit) and plug the  standard standalone flasher (3 prong) on the flasher terminal (4 pin female) which is near the 12 pin female connectors that feed steering and instrument cluster respectively.   

If by doing so we find that turn signals are now operational, the following step would be to connect both hazard relay on 6 pin terminal, and fasher in 4 pin terminal, to see if they work with each other without conflicting signals. 


Best regards
Leonardo Peterssen
Www.wiredoktor.com

[lpeterssen]

This is not needed in your case

[lpeterssen]

Connect here the hazard relay.

[lpeterssen]

And after the flasher here

[CJHenderson]

That has always been in the car since we have owned it.

[CJHenderson]

Removed the three-way harness and reinstalled the hazard switch everything worked great had turn signals and hazard flashing, and then, and then, fuse block started smoking from fuse 5, fuse did not blow just warped, this is the fuse that covers what you all and I have been working on. There is a shot of scotch in my future.