New gmt 400 owner, wondering what these are for

[Kavenadams]

I have a 91 Chevy c1500 Silverado with a 5.7 and 4L60E 2wd. I noticed the slider and the button and constantly pressed it trying to figure out what it’s for and to my avail I still don’t know what it’s for. Anyone know for sure?

 

[AK49BWL]

Cruise control.... Switch in the middle turns the system on. Over 25mph if you hit the button on the end it will engage the cruise module. push the switch to the right will accelerate, push and hold the button on the end to decel. far left is off.

 

[someotherguy]

Brandon beat me to it, but I'll add, if it's not working as expected (now that you know what the switches do) - it's very common for the lever to have broken wires in the bend where they go into the column. Somewhat less common but if the previous owner didn't use the cruise, the switches can get dirty/oxidized contacts. I've revived a few of them by spraying lots of DeOxit contact cleaner into them and "work" the switches a bunch until they begin responding.

BTW your '91 will have the 700R4/4L60 transmission, no "E" on the end. It uses a cable (throttle valve cable, referred to as the TV cable) from your throttle body down to the transmission in order to control line pressure and shift behavior. You'll see it mentioned quite a bit when discussing transmissions in these trucks, and its adjustment is critical to the life of your transmission. If it's behaving correctly, don't mess with it. In 1993 the 4L60E hit the scene in the light duty trucks and is electronically controlled, eliminating the TV cable.

Richard

 

[AK49BWL]

And if it engages but the truck starts shuddering and freaking the hell out, you've got a worn out worm gear or solenoid in the cruise module and the module will have to be replaced. My Dad's 90 had this issue.

 

[Kavenadams]

Cruise control.... Switch in the middle turns the system on. Over 25mph if you hit the button on the end it will engage the cruise module. push the switch to the right will accelerate, push and hold the button on the end to decel. far left is off.

Thank you so much, this really helps me

 

[Kavenadams]

Brandon beat me to it, but I'll add, if it's not working as expected (now that you know what the switches do) - it's very common for the lever to have broken wires in the bend where they go into the column. Somewhat less common but if the previous owner didn't use the cruise, the switches can get dirty/oxidized contacts. I've revived a few of them by spraying lots of DeOxit contact cleaner into them and "work" the switches a bunch until they begin responding.

BTW your '91 will have the 700R4/4L60 transmission, no "E" on the end. It uses a cable (throttle valve cable, referred to as the TV cable) from your throttle body down to the transmission in order to control line pressure and shift behavior. You'll see it mentioned quite a bit when discussing transmissions in these trucks, and its adjustment is critical to the life of your transmission. If it's behaving correctly, don't mess with it. In 1993 the 4L60E hit the scene in the light duty trucks and is electronically controlled, eliminating the TV cable.

Richard

I was just about to pay someone to install cruise control on the truck because I have to drive 4 hours and I only get about 12 mpg highway and I hoped cruise control would help. And thank you for the information about the transmission, this is my first truck I bought for $900 and I’m trying to learn everything I can so I don’t have to pay people to work on it.

 

[Caman96]

All this time you thought you had surface to air missles.

 

[SlowZ71]

Cruise control.... Switch in the middle turns the system on. Over 25mph if you hit the button on the end it will engage the cruise module. push the switch to the right will accelerate, push and hold the button on the end to decel. far left is off.

I’m not gonna lie, I’ve owned a GM product with that cruise control style for 13 years and never knew that… ‍
ETA: the cruise decel part at least. I knew the function and accel.

 

[GoToGuy]

Soooo... This might be a good time to get the handbook, the owners manual? It does have a lot of great info. Fuses, locations size, bulbs , size how to change all the welcome to GM truck info. All the fun simple stuff that can be frustrating the first time. The " GM heritage " site now has a huge download available library of GM materials. And the glovebox owners handbook is just one of many materials available. Check it out!

 

[GoToGuy]

This is what's supposed to look like, but the white print wears off pretty easy. So you end up blank stalk. One trick. Is when you reach the speed you want to cruise at. One tap of the end button. Or you can slide tap the the R/A ( resume/accelerate ) to engage cruise speed.

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