1981 MC9 Intermittent Turn Signals/Hazard Flashers

[Debo]

Hi all. I'm having an issue that I suspect is the turn signal flasher on my 81 MC9  . At times, the signals operate perfectly, and others, the turn signals and hazards are dead. I'm assuming it's the flasher, but I'm a little puzzled. It looks like the bank of 6 flashers in the drivers side control box are dedicated to other things - not turn signals. There's another silver relay in there that I suspect is the one, but it's only got 2 wires going to it. Part# 150-66. Another part number is 159-906. It appears to be a 24v relay. My schematic is from a few years after my bus was built, and it appears there were some changes in the interim. So... am I on the right track here? Is there any way to test a bad flasher? Thanks I'm advance for any assistance you can provide.

[richard5933]

Some relays only have 2 wires.

You could also have a bad ground connection, especially if the problem is intermittent. Ground problems due to rust/corrosion/loose connections/etc. probably account for over half of this type of electrical issue.

[buswarrior]

The flasher unit is inside, above your left foot, round, had a matching clip against the wall in the corner.

All the rest of that stuff you described out in the electric box are relays for other things.

Start with the flasher, and the wiring leading to it.

Happy coaching!
Buswarrior

[dtcerrato]

Hi all. I'm having an issue that I suspect is the turn signal flasher on my 81 MC9  . At times, the signals operate perfectly, and others, the turn signals and hazards are dead. I'm assuming it's the flasher, but I'm a little puzzled. It looks like the bank of 6 flashers in the drivers side control box are dedicated to other things - not turn signals. There's another silver relay in there that I suspect is the one, but it's only got 2 wires going to it. Part# 150-66. Another part number is 159-906. It appears to be a 24v relay. My schematic is from a few years after my bus was built, and it appears there were some changes in the interim. So... am I on the right track here? Is there any way to test a bad flasher? Thanks I'm advance for any assistance you can provide.

That same issue plagued our flashers for a long long time before finding out that it was a faulty circuit breaker that when heated by load tripped until cool down. It drove us crazy for the longest time...

[Debo]

This is all great stuff, guys. Thank you so much. We're currently traveling in the bus, so I'll troubleshoot and let you know what I find. Thanks again.

[Debo]

Hello all. I'm home from my trip, and I thought I'd report what I found out about my turn signal issue to maybe help out someone in the future. Here's the scoop...

Tracked down the circuit breaker as suggested by dtcerrato, and it turned out to be working correctly. Thanks for the suggestion, though. Helped me narrow things down.

I found the flasher unit inside the driver's area above my left foot as suggested by buswarrior, and it appeared t be working correctly as well, although I think it had been replaced at some point. It was a small rectangular plastic box with some crimp connectors on it, so definitely not factory, but working fine nonetheless.

The relay I reported in the original post located in the front junction box was indeed part of the system, but it looks like it was part of an option to have an extra set of turn signals above and between the rear wheels - at least that what it appears to be from the schematic. I don't have, and it appears I never had turn signals in that area - just the standard front, rear, and two on the forward sides, so it appears to be supplying power going nowhere.

I could tap on the relay and it would click in rhythm supplied by the flasher, but it would work intermittently. Since it doesn't appear to be used, I unplugged power (#45) from it, and have had reliable turn signal and hazard light operation ever since.

Hope this helps someone in the archives down the road.