What are these things under the dash?

[72chevy2door]

Hey guys and gals I have a couple of questions as to what these things are. It's on a 1988 gmc 1500 2wd suburban. The black with aluminum fins is located under the column and the blue plastic thing is located behind the headlight switch. What are they and what do they do? I've never seen them before on anything before other than me and my brothers truck. Both are the same trucks mostly.

 

[72chevy2door]

The blue thing

 

[chunkyrzr]

the first one is for internittant wipers--the other i don't know

 

[GTME94]

I think the blue box is the optical encoder for the cruise control.

 

[72chevy2door]

Ohhh ok. Thank you guys. I had no idea what they where.

 

[foamypirate]

I think the blue box is the optical encoder for the cruise control.

In this case, being an 88', it also feeds the TBI ECM.

 

[72chevy2door]

What does it do for the tbi? Tells it when to lock up converter in transmission or something?

 

[chengny]

It tells the Cruise Master how fast you are going. Let it be.

 

[72chevy2door]

I wasent going to remove them I was just under the dash and seen them so it made me curious. Thanks guys for the info

 

[foamypirate]

What does it do for the tbi? Tells it when to lock up converter in transmission or something?

It lets the ECM know vehicle speed for idle control when coming to a stop, TC lockup, etc.

 

[72chevy2door]

Ahh thank you foamy pirate. It's weird never seen one before so I figured I'd ask. Thanks again guys