The turn signals on my '84 300D stopped working the other night. Fuses are OK, bulbs are OK so I'm starting to dig a bit deeper.

The hazard flasher switch is definitely broken - that wasn't working prior to the turn signal failure, a replacement is on route but since that wasn't working and the turn signals were I don't think replacing that switch will bring back the turn signal.

The relay seems like the next logical step here. Since both the left and right signals failed at the same time I kinda doubt the switch is the problem, of course it could be a short somewhere...

My wallet protest mightily when I start buying new components in the guessing game diagnostic system. Does anyone know of a way to test a relay? Can I meter it somehow?

A quick and easy way to find out if the switch is at fault:

Get a piece of wire and make a connection across the terminals of the switch, if your turn signals flash the relays OK, if they stay ON its broken!

Easy!!

A typical simple automotive relay has 2 terminals on either side of an electromagnetic coil. there should be continuity across these 2 terminals. Applying 12VDC across them, contact should be made across 2 other terminals on the relay. A turn signal flasher is different however, as I believe it uses capacitance to control the "flashing".

__________________
'82 300SD - 361K mi - "Blue"

"Good judgement comes from experience. Experience comes from bad judgement."

listen, look, .........and duck.

Shake it, see if it rattles


It's not supposed to

the flashers ant the turnsignals are definately related, i would wait for the flasher switch before you go much further,

the relays can be tested as long as you know the function of its one, meaning that not all the realys are the same.
Some open one circuit and close another while others close 2 circuits and open another and so on. I think there about 5-6 different types for each car maybe more.