ABS and 4WD Question?

kenny jacobs · November 17, 2003

I have a 1999 Z-71. My service 4wd lights comes on at times.

I can turn the truck off and it stays off for days. I was told that I need to clean the sensors at the wheel. Does that sound correct?Also, I need to know how to check and see if my ABS is working? I am having poor braking performance. The pedal doesnt pulse under pressure. All help would be appreciated.

silverado man · November 17, 2003

I'm sure it is the switch on the dash. Mine did the same thing about 1.5 yrs ago and I replaced it and haven't had a problem since. Does the lights on the switch go out at times? And if you tap the dash do the kind of flicker? Those were a couple more symptoms that I had. Do a search on this forum and you'll be able to find the part number for the switch. And then you can visit one of the supporting parts vendors to order the part for almost half the cost of buying it from your local dealer.

ness5575 · November 17, 2003

when my service 4wd light came on, i ended up needing a new switch (with the buttons 2-HI, Autotrac, 4HI, and 4-LO). Mine was under warranty, but i think that it is $60-70 for a new unit.

Z71GUY · November 17, 2003

when my service 4wd light came on, i ended up needing a new switch (with the buttons 2-HI, Autotrac, 4HI, and 4-LO). Mine was under warranty, but i think that it is $60-70 for a new unit.

I got mine from my dealer for $40. 60-70 is a bit high

AZ-Z71 · November 17, 2003

Bought mine about two years ago for around $27.

TexasZ71 · November 18, 2003

Hey SilveradoMan,

I am having the same problems you experienced. The service 4WD light has come on a couple of times in last 2 weeks and the dash light around the 4x4 buttons has gone out 4 or 5 times. A slight tap on the dash will get the dash lights to come back on.

I asked a couple of the dealers if these two items were related but, they didn't know anything about it. I have seen the service bulletin on the bad swithces. I was hoping this was the problem. I'm out of warranty and checking one of the on line part sources the switch (part # 15709327) costs $31.26. I'm glad to here this is the cure for both of my problems.

Is this switch very had to change out? I would think it should be very simple. How was it for you?

Thanks Brian

silverado man · November 18, 2003

I'm no mechanic and if you know how to put a plug in an outlet you can do this job. All you have to do it put the tilt on your steering all the way down and the shifter in 1st gear (make sure parking break is set). Then take the dash bezel off, start by pulling it away from the dash in the upper left hand corner and work your way around (make sure you take your time so not to break any plastic tabs, also make sure that you didn't loose any of the little rubber things you'll know what I'm talking about when you get it off). When you get the bezel off you can now work on the switch part. Just take and push or pull (can't remember which you'll figure it out just by looking at it) the little clips that hold it in or out then the switch will be free to be pull out unplug it and plug in the new one reassemble. Its a very easy job. Hope this helps you out.

kenny jacobs · November 18, 2003

Thanks for all of the replys. I will change my switch. Sounds easy.

How about the ABS thou? Doesnt seem like my truck wants to stop

Thanks, Kenny

frdfandc · November 19, 2003

ABS - stands for Anti-lock braking system. The ABS only works in a panic stop. Like if someone cuts you off and you have to jam on the brakes. The ABS also works in inclement weather (snow,rain) and also on slippery surfaces (dirt,sand) if it indicates that one or more of the wheels are going to lock up. The ABS has NOTHING to do with your normal braking performance. Have you had your brakes checked recently???? If your brake pads are worn down low (on the verg of needing replacement) your brake performance will suffer.