I believe the brake switch is located on the brake pedal assembly. As to cost, I'm not sure there either but I'd imagine not much. I'd call a couple parts houses and see what they pull up for ya.

As for testing the TPS, you'll need a voltmeter. Get a meter that has the sharp pointed leads (for penetrating the outer wire jacket). Do this:
-turn ignition to ON
-penetrate the center wire of the TPS with the positve lead.
-connect the negative lead to the negative bat terminal.
-set the meter to 20V DC(or somewhere close)
-the voltage should be around .7V
-slowly open the throttlebody with your hand and watch the meter. The voltage should slowly increase with your hand movement. Watch the meter for dead spots or sudden jumps in voltage. If you get any, replace the TPS.
-WOT voltage should be (IIRC) around 5-5.5V.

 

when you tap the brake and it makes the tc unlock it is doing what it is supposed to do. if the brake switch was bad then hitting a bump would disengage the cruise. i'm pretty sure i'm right about that one.

the tps test is done with a multimeter. i believe you need to have the key on to check it (haynes manual doesn't say if you do or not but i did and it read correctly). back probe the plug with it connected to the tps. put the + in the orange/dark blue wire and the - into the black/light blue wire. with the throttle closed it should read .5-1.5 volts and with it fully open it should read 3.5-4.5 volts. when you are opening the throttle the voltage should move smoothly up and when letting it close it should smoothly drop. the voltage shouldn't go over 5. anything other than that and it is more than likely shot.

you can check the voltage at the wires with it unplugged first but when one goes bad its normally the tps and not the wire that powers it. if you're gonna check the wire first the + probe goes into the purple/white wire and the - goes into the black/light blue wire. it should be 5 volts.

i'm quoting the haynes manual by the way. and with a good tps on mine the haynes manual is spot on with the voltage.

 

I couldn't remember what the WOT voltage was. Thanks for the reminder.

My question is, why would the TPS cause the TC to unlock? The only way I can see this happening is maybe the voltage on the TPS is spiking making the PCM think he is flooring the gas pedal briefly so it sends the unlock signal to the tranny, but since the gas pedal is not physically moving, the tranny is not downshifting because kickdown cable is not moving. OR....upon further thinking, maybe the voltage on the TPS is dropping sunddenly causing the TC to unlock (to coast) but since the pedal has not moved, the engine remains under load and at a higher RPM due to the TB being held open.

Hmm....I'm definitely not arguing with you, Sherrif. I hope you don't think I am. Running the TPS through my brain (as small as it is), you may have a point here. Have you ever thought as you typed? It can be very confusing on a forum. LOL!

To the OP: if you don't want to test the TPS, just replace it. They're about 20 bucks and easy as pie to change out.

 

OK, I might just change out both, just as PM, if the brake switch isn't that bad in price. LOL


Thanks again.

 

The CC dropout contact, PCM signal, and brake light contacts are all seperate on our brake switches. So if one contact is closing slightly earlier than the rest (eg: PCM) it could cause the TC to unlock without dropping out the CC or turning the brake lights on. The switches are all in the same housing, but if you look at the schematics they are seperate internally.

A quick and dirty way to see if it's a dirty TPS: when the TC is dropping out frequently, gently increase/decrease the throttle position (preferably with the CC on for more consistent results) about a dozen times. If the TC dropout ceases for a while, chances are it's a dirty pot (TPS). Replace TPS. The range of throttle you use for highway cruising is the first portion that's going to wear out.

 

I did not know the brake switch had seperate contacts! GREAT INFO!

 

the tps is about 40$. and i'm glad someone got on here that knows something about the brake switch. i believe i'm gonna look into mine to see if i can get my surge to go away. i never thought to check it because i figured if was bad that it would kick out of OD on every bump.

 

Know what you're talking about before whining about it.

I mentioned the IAC not moving, never did I say anything about the voltage testing not working. The Haynes describes both, IIRC.

I didn't jump on you, as I recall. In one thread, I mentioned that for some models, it may not move at all when the key is in the "ON" position after you posted the test procedure. Then you repeated the test procedure in another thread later, without mentioning that it may not work for some model years, so I mentioned it again. I was simply trying to possibly save someone some $$$ for thinking its bad and replacing it when it may not have been, as I had done.

Mine didn't move, I thought it was bad. Purchased a new one, it didn't move either, and didn't solve my issue. Ended up with two good IACs, wasted $$$.

 

I'd be leery of a $20 TPS, I paid $60 at NAPA.

 

Yea, I realized later that my cost was a bit low. It's been a while since I replaced mine (I've slept since then ).