One of the few remaining problems in my truck is the brake light (on dash) keeps coming on. My buddies snap-on scan tool said it was the rez switch. Before I shell out the $80 to replace the whole rez and switch, is there a way to trouble shoot it? To make sure that's actually the problem?

Truck is an 06 1500 mega cab hemi 2wd (if it matters)

 

Try unplugging the rez switch and see if the light goes away.

 

As I suspected, when unplugged, the light is always on.

Can someone pull the plug on theirs and read it with an ohm meter?

 

Ok. Teach me something. What is a rez switch?

 

Brake fluid reservoir switch. The container on top of the master cylinder.

 

Ok thanks. Low fluid sensor. Only thing I can think of is that build up of a more solid substance that is sometimes observed in master cylinder reservoirs? May be messing with the sensor?

 

So I hit the bullet and just ordered a new fluid reservoir that has the switch built in. (only way you can get them it seems) it was only $53 in Amazon and is a Mopar part. Put the ohm meter on it and it's a rock solid 79k ohms when upside-down (as if full). The one on my truck would bounce around from somewhere in that range all the way to 300k ohms. I'm hoping this will fix it. Now I just have to figure out how to replace it.

 

So, it's just one star-headed pin holding it on and then it just pops right out of the master cylinder. Hoping that fixes it.

 

you got it right. if you want to test the wiring...jumper the connector pins and the light should got off.