question how cruise control works

ok I just got a 99 sr5 ext cab with Toyota factory cruise control and I noticed the cruise control acts funny.

by that I mean when set it works fine to bump the accelerate button to speed up and bumping the set button drops the speed 1 or 2 mph as you would expect but the funny part is if I tap the brakes and it kicks off, I try to hit the up/resume button and nothing happens. every time I tap the brakes I must manually reset my speed where i want it.

in my chevy it would resume when I hit resume after taping the brakes so I assume the cruise control isn't working right and wondered what, if anything, I can do to fix it and where I might look for the problem to be. is there a control circuit board I need to replace somewhere?

I don't think it has anything to do with the control knob since the accelerate button is the same button and it works just fine, in fact everything about it works just fine except when you tap resume its like there is no preset memory to return to your previously set speed.

thanks for your help on this

 

I'm not sure where you truck is from or if it has "OEM Cruise Control", but there is a recall notice for the 96 Tacoma related to aftermarket cruise control:

THESE CRUISE CONTROL SYSTEMS FAIL TO HOLD THE SPEED SET BY THE DRIVER AND CAN ACCELERATE ABOVE THE INTENDED SET SPEED. UNINTENDED ACCELERATION CAN INCREASE THE POTENTIAL FOR A VEHICLE ACCIDENT. DEALERS WILL REPLACE THESE CRUISE CONTROL ASSEMBLIES.

SYSTEM: FUEL; THROTTLE LINKAGES AND CONTROL EQUIPMENT DESCRIPTION: AFTER MARKET CRUISE CONTROL SYSTEM INSTALLED ON CERTAIN TOYOTA PASSENGER VEHICLES AND LIGHT DUTY PICKUP TRUCKS SOLD IN TOYOTA DEALERSHIPS SERVICED BY SOUTHEAST TOYOTA AND GULF STATES TOYOTA DISTRIBUTORS. THE DEALERS WOULD BE LOCATED IN THE FOLLOWING STATES: FLORIDA, ALABAMA, GEORGIA, NORTH CAROLINA, AND SOUTH CAROLINA FOR SOUTHEAST TOYOTA AND TEXAS, OKLAHOMA, MISSISSIPPI, LOUISIANA, AND ARKANSAS FOR GULF STATES TOYOTA.

NOTE: OWNERS WHO TAKE THEIR VEHICLES TO AN AUTHORIZED DEALER IN THESE AFFECTED STATES, ON AN AGREED UPON SERVICE DATE AND DO NOT RECEIVE THE FREE REMEDY WITHIN A REASONABLE TIME SHOULD CONTACT ROSTRA AT 1-910-276-4853 OR TOYOTA AT 1-800-331-4331. ALSO CONTACT THE NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION'S AUTO SAFETY HOTLINE AT 1-800-424-9393.

1900 ROSTRA CRUISE CONTROL
1996 TOYOTA CAMRY
1996 TOYOTA CELICA
1996 TOYOTA COROLLA
1996 TOYOTA TRUCK T100
1996 TOYOTA TRUCK TACOMA

 

no im a 1999 and its 100% Toyota factory cruise not aftermarket

I guess im just trying to find out where the "brain" circuit is and if anyone ever had an issue like this before and might know of a fix for it before I just replace it.

im pretty sure that the brain circuit has to be whats bad since all the switch functions and the cruise settings all function perfectly.

its like it has lost the ability to store the last speed setting in its memory but other then that it all works perfectly as it should.

I suppose the brain is somewhere inside that box looking thing under the hood?

mine does not have that round can with the vacuum diaphragm style, its more like a square boxed looking unit with a vertical shaft coming out the top and two cables connected to it similar to the throttle body throttle linkages

 

ok the box under the hood says its the cruise control actuator, it has 4 wires going to it and it says: Toyota 88002-35080 / Denso 100300-6090

so is that my cruise control control unit box or is the cruise control brain unit somewhere else?

I see cruise control units on ebay that say they are for my year truck and look like this: http://www.ebay.com/itm/99-00-TOYOT...ssories&hash=item51c487a734&vxp=mtr#vi-ilComp

the cruise control actuator under the hood looks nothing like that at all so I must be looking at the wrong thing so where is my cruise control ecm located and how do I get to it?

yes I know I need to get s FSM but until then please help?

 

I have the same problem don't care to dick with it lol

 

well im told when it starts acting up on you it can do anything and may send you at full throttle or just not turn off anymore without any warning so if your not gonna fix it you might want to just unplug it for safety. just sayin

I found something that looks like it under the ash tray under that bottom dash trim piece, but it has 3 yellow colored wire plugs going into it so I think maybe that control unit is for the air bag system?

 

I installed a factory cruise in my 2002 Tacoma with 2.7, auto. For this unit there's a computer for just the cruise located behind the kick panel on the passenger side. Expensive to replace, have heard of some used units available from wrecking yards. This computer is exclusive to your drivetrain, i.e. V-6 auto and stick would different, 4 banger yet a different unit. Some 4 Runner parts are interchangeable.

 

ok thanks, was yours 2wd or 4wd?

I got a book on old tacomas '89 and it says its in the drivers side kick panel so its got to be behind one of em lol.

they list three numbers for my truck so that's why I wanted to see what number mine was so I get the right one.

I may call the dealer once I have my number and ask which part numbers cross over then look around for a used one.

thanks for the tip