850 turn signal switch replacement

Post by **cn90** » 16 Apr 2017, 20:28

I have a $1M dollar question: can the hazard switch (located below the Radio) fail in such a way that the hazard function works (all 4 lights at 4 corners blinking) but the "Turn Signal" function inside the hazard switch fails?

Post by **BEJinFbk** » 17 Apr 2017, 01:29

cn90 wrote: 16 Apr 2017, 20:28 I have a $1M dollar question: can the hazard switch (located below the Radio) fail in such a way that the hazard function works (all 4 lights at 4 corners blinking) but the "Turn Signal" function inside the hazard switch fails?

Absolutely - It's hands down the most common way that they fail.

Teddy1975 · Post by **Teddy1975** » 17 Apr 2017, 01:56

With all electronics inside the hazard lights switch, I'd say yes.

Have a look at this: https://volvo850wagon.wordpress.com/201 ... -relay-pm/

Post by **abscate** » 17 Apr 2017, 04:28

I've got a bunch of free ones as Evan paid me a free one forward. Pm me and I'll find and ship

Catch me before I'm on travel to nasty parts of world this week, though, if you are in a hurry

Post by **cn90** » 17 Apr 2017, 07:11

Thanks abscate, I have a junk yard nearby, I will go there today and pick up BOTH the turn signal assembly + the hazard switch.
Thanks for the offer though!

The posts by BEJinFbk and Teddy1975 seem to contradict each other.

My review of the electrical diagram shows that:

Battery ---> Ignition Switch ---> Fuse #27 ---> Hazard Switch ---> Turn Signal Stalk ---> R or L turn signal lights.
YELLOW arrows show the path from battery ---> Turn Signal lights.

See diagram below:

: Volvo-Turn-Signal.jpg (257.04 KiB) Viewed 967 times

Teddy1975 · Post by **Teddy1975** » 17 Apr 2017, 07:57

cn90 wrote: 17 Apr 2017, 07:11 The posts by BEJinFbk and Teddy1975 seem to contradict each other.

I'm not sure why, you'd think so. I'm fully agreeing with BEJ

As you say, the power runs through the hazard switch assembly on the way to the signal lights with a branch out to the turn signal stalk. So a problem with the circuit board in the hazard switch can cut the flow of power to the stalk = turn signal not working while hazards work fine.

/Teddy

Post by **cn90** » 17 Apr 2017, 10:11

Teddy1975,

I am thinking problem with Connector 24/13, yellow arrow ---> Turn Signal Stalk.
This explains my symptoms.

This is b/c if you look at the Hazard Switch, the power supply for the hazard switch and the wire (GN-R) that feed the Turn Signal is the same.
So the "break" has to be downstream of the hazard switch.

Post by **cn90** » 17 Apr 2017, 12:07

Thanks to jblackburn, he just updated the other thread, the problem (per jblackburn) was the Ignition Switch.

viewtopic.php?f=1&t=15383

Post by **erikv11** » 17 Apr 2017, 12:40

Wow, you already fixed it? Now *that* was fast!

Was it the original electrical portion, or had you changed it already?

Post by **abscate** » 17 Apr 2017, 14:02

you need advanced equipment to test the turn signal switch - see here

: Screen Shot 2017-04-17 at 4.03.27 PM.png (1.18 MiB) Viewed 908 times

Careful study of the waveform reveals why the cruise was inoperative