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Replacing Indicator Relays

Started by Alex, 05 March 2024, 01:01 AM

Alex

Hi all,
So I had a previous thread about a fast indicator, this is the continuation, but more specific to the issue.

Issue: The indicator flashes about 2x as fast as it should.

Testing: I removed and replaced all indicator bulbs with brand new (P21W/ BA15S 21watt) ones. The issue is not fixed.

Diagnosis: I believe the issue is related to a worn out flasher relay. Now, how does on access said relay? And is it just 1 relay? Or are there multiple?

And likewise, I found numerous repco (auto store) relays $10-$30, they have 3 pins (in, flash, gnd). How would this work with the existing wiring?
77' 280SE Classic White (198,000km)

daantjie

Does your hazard/flasher button work?  I recall that problems with indicators might have something to do with a faulty hazard switch.
Daniel
1977 450 SEL 6.9 - Astralsilber

Alex

Quote from: daantjie on 05 March 2024, 01:06 AMDoes your hazard/flasher button work?  I recall that problems with indicators might have something to do with a faulty hazard switch.
works
77' 280SE Classic White (198,000km)

Jed

Some cars have the relay built into the large hazard switch relay in the center console.  Other models have a separate relay under dash.  Just follow the clicking noise when the turn signal is on and that's the relay.

Before I would start messing with the relay I would not only change the bulbs but be sure all the contacts are good and not corroded/oxidized, including the grounds on all the light bulbs.  A fast flashing turn signal usually means too much resistance/a bulb is out.  If all the bulbs are working you may still have too much resistance due to corrosion or a bad contact.

i would not mess around with aftermarket relays  Get the correct OEM style relay. Some are reasonabley priced and some are not...
1979 Mercedes 6.9 #5206 - restored
1979 Mercedes 6.9 #6424 - ongoing restoration
1976 Mercedes 6.9 #484 - restoration?

Alex

#4
Quote from: Jed on 16 March 2024, 02:59 PMSome cars have the relay built into the large hazard switch relay in the center console.  Other models have a separate relay under dash.  Just follow the clicking noise when the turn signal is on and that's the relay.

Before I would start messing with the relay I would not only change the bulbs but be sure all the contacts are good and not corroded/oxidized, including the grounds on all the light bulbs.  A fast flashing turn signal usually means too much resistance/a bulb is out.  If all the bulbs are working you may still have too much resistance due to corrosion or a bad contact.

i would not mess around with aftermarket relays  Get the correct OEM style relay. Some are reasonabley priced and some are not...

I replaced all bulbs so that isn't it. The wires all looked good and fine, (untouched since 1977 purchase).

https://www.repco.com.au/globes-batteries-electrical/electrical-accessories/flashers-relays/tridon-flasher-12v-3-pin-hd13/p/A4070658
^ I might just chuck one of these in. Thoughts? - I reckon it should just work..

The bulbs I have in currently are 21W. (ba15s). And the flasher takes 11-15v, and its a consistent speed.
77' 280SE Classic White (198,000km)

Pete49

search for Topklasse its a aussie forum board dealing in W117 models. Also in Ozbenz forum is an answer regarding thisvery question and how to adjust the aftermarket one work correctly.
What this country needs are more unemployed politicians.
Edward Langley,  Artist (1928-1995)

Gpapaniko

My relay was under the dash on my 1980 280SEL, replaced it after slow flashing or indicators remaining stuck on.  Original OEM from Pelican Parts at around AU$250. Now works fine.  Fast flashing (if consistent) is a sign of bulb out not a relay in my experience.  One way to check is to swap out with a working relay from a mate with the same relay and see what happens then decide.  Check if bulbs and internal indicators work, you may also have a short in the rear tail light assembly - I'd give that a clean as well with some electrical contact cleaner.  Good luck
Never stop loving
1980 280SEL

Alex

Quote from: Gpapaniko on 26 March 2024, 06:24 AMMy relay was under the dash on my 1980 280SEL, replaced it after slow flashing or indicators remaining stuck on.  Original OEM from Pelican Parts at around AU$250. Now works fine.  Fast flashing (if consistent) is a sign of bulb out not a relay in my experience.  One way to check is to swap out with a working relay from a mate with the same relay and see what happens then decide.  Check if bulbs and internal indicators work, you may also have a short in the rear tail light assembly - I'd give that a clean as well with some electrical contact cleaner.  Good luck

Don't have any mates with the same relay to be borrowing.

I have swapped the bulbs with fresh ones, and the issue persists. When I didn't have a bulb at all, it was real quick. (So the relay is changing with varied resistance). The internal indicators work fine. Where would a short for the rear tail light assembly be? - the housing is plastic.

Thoughts on aftermarket relays?
77' 280SE Classic White (198,000km)

Gpapaniko

I'd use genuine or a very good auto electrician may have an alternative
Never stop loving
1980 280SEL

rumb

#9
Check the resistance and voltage  of wires in each socket. I would expect them to be similar.

Also be aware bad grounds lead to problems. The main ground for the rear harness is behind the RR passenger seat.
'68 250S
'77 6.9 Euro
'91 300SE,
'98 SL500
'14 CLS550,
'16 AMG GTS
'21 E450 Cabrio

Alex

Quote from: rumb on 27 March 2024, 08:28 AMCheck the resistance and voltage  of wires in each socket. I would expect them to be similar.

Also be aware bad grounds lead to problems. The main ground for the rear harness is behind the RR passenger seat.

I will take a look at the grounding cable this afternoon. If the resistance of the wires is different, would it be best to just replace them?
77' 280SE Classic White (198,000km)

rumb

Not so much replace as it would be fixing. Replacing wires isnt fun.
'68 250S
'77 6.9 Euro
'91 300SE,
'98 SL500
'14 CLS550,
'16 AMG GTS
'21 E450 Cabrio

Alex

Had a look the other day, could not for the life of me- find that ground.
I found "a" ground, and I fixed that up, but it was for something else entirely.
Any photos of what I am looking for? (Also its a RHD car)
77' 280SE Classic White (198,000km)

Jackhammer

You can always buy the cheapo generic one, and test if it would solve your problem. Is your relay 4 pin or 3 pin?
My original one died in the city, (rush hour ofcourse), so I just bought the generic 3 pin one, and it works like a charm, although it's quite quieter than the OEM one

Alex

Quote from: Jackhammer on 04 April 2024, 04:41 AMYou can always buy the cheapo generic one, and test if it would solve your problem. Is your relay 4 pin or 3 pin?
My original one died in the city, (rush hour ofcourse), so I just bought the generic 3 pin one, and it works like a charm, although it's quite quieter than the OEM one

When I get a chance I'll pull the relay and out and see what it is.

I would need to fabricate some new connectors for an aftermarket one to fit right?

And is there any risk with an after market one (it should just work if the amperage range is the same).
77' 280SE Classic White (198,000km)