Symptoms : I started having problems with my turn signal clicking even when the switch was in the neutral position. It will click almost constantly when the ignition is turned on/running. The clicking is the same rhythm as if you had turn signal/hazards on. All signal lights work properly and only flash when they're supposed to. The clicking noise stops when the brake is applied. This leads me to believe that is the multifunction switch or the relay.


Question : Now before I start ripping into the dash and pulling the steering wheel, I was curious if it could be a corroded/loose ground wire, but I'm not sure where it is located. I saw this same issue in a few other topics but couldn't find anything on the grounds. Thanks in advance


EDIT: this is a 1999 Blazer 4dr 4wd 4.3L

 

That is the classic Hazard switch failure.. there are many other symptoms but it's the one I had.

Note that your turn signals may work properly but your brake lights may or may not, depending.

https://blazerforum.com/forum/tech-a...acement-37435/

Read that carefully and follow all directions, there are two versions of the switch.
Here's one .. from Rockauto


DORMAN Part # 924608
Stamped 15177379
$9.62



According to the Dorman catalog that replaces BOTH versions
http://www.dormanproducts.com/c-429-...-switches.aspx

 

Here's a few others from the Tech Article (DIY) section:
Broken Hazard Switch Repair
98+ Hazard Switch Replacement

GM has a TSB out for this condition in which they recommend attempting to replace the hazard switch only. If that doesn't work, then the whole multifunction switch will need to be swapped.

 

Thanks, I will replace the hazard switch first then. The brake lights work fine also, I am a little curious as to why pushing in the brake pedal causes it to stop clicking. Does anyone know how the brake lights are tied in to the hazard/turn signal circuits?

 

Sure we do.. they are on just about every car. The only exception is the center mounted stop lite.

But despite being trained in electronics and computer logic, I found early on that some circuitry was based on relay logic.. or if you prefer 'pinball machine' logic. I HATE Carburetors and I hate pinball relay logic.
but that's just me.
I can get by with most single layers of switch/relay logic.. and fortunately most circuits have that.

Specifically, looking at the ppl wire -C1- to the flasher, you'll see with a meter that when you press brake, the voltage will change {backfed} and flasher no longer sense current through the stop lights. This is enough to overcome the minute voltage sensed through bad connection via B1. I'm not gonna mention that diagram makes no sense when you look at B1's connection logic on Util {blazer} vs the Pickup {S10}