MARF75

I was taking apart my dash and arced the POT and the map lite out on each other.
Now I have no OD. What did I burn up? It popped the fuse for the interior lights. Did I burn up the POT switch? Help need OD soon for the highway trip tomorrow.

MARF75

Nobody has any input??

j_martin

What Pot?

MARF75

Potentiometer
I replaced my TPS with a potentiometer per the sticky a few months back. The above incident happened this weekend.

j_martin

The TPS pot is in a 5 volt control circuit. The 5 Volts is supplied by the PCU. Other sensors, such as VSS and CPS use the same 5 volts.

Either you wacked the PCU, or the pot and/or other sensors by hitting them with relatively unrestrained (amps vs milliamps) 12V.

Measure the voltage available at the pot when the key is on. Should be 5V at one end, ground at the other, and the middle one depends on the position.

j_martin

When yer done mopping up the carnage, reinstall the pot with a few cents worth of heat shrink over the connections.

MARF75

You must have read my mind. I do my best to learn from my mistakes, although my best isn't always good enough. Thanks for your replies

MARF75

Ok J, 5 volts at 1 side of the pot, variable volts between 0-5, adjustable with the ****, on the center terminal and the other is grounded.
PCM and POT still good?

j_martin

What else doesn't work?

Odds are pretty good that you hit the ground terminal and only hurt the fuse. There must be something else going on.

MARF75

Overdrive and the heater blower motor. As for the blower motor,I have ignition switched 12v on the brown wire coming in the back of the HVAC control panel. However no power coming out of the fan speed switch or the plug that plugs in the back of the fan switch.

MARF75

I checked the blower motor fuse, it was fine. But I changed it out with another 30 amp just to be sure. I've heard of fuses being bad but not showing it.

j_martin

You're down to actually troubleshooting the overdrive system.

MARF75

Well after poking around. Behind the dash after work Tuesday night, still no blower motor but the overdrive is working now!
I don't know why or what could have fixed it but it works.

j_martin

I think you'd have to delve deep into chaos theory to figure that one out.

Mark Nixon

I wouldn't feel so confident that the trouble is past, if I were you.
You may well have seared the resistance strip in the POT, maybe adjusting it around re-seated the finger, or whatever that type of set-up uses.

I'd get another pot assembly and keep it on hand, or install it.

Keep in mind, it's ALWAYS when you go on the road after something like this happens, that it turns into the hell ride of your life.

I believe in Mr. Murphy.
Mr. Murphy's Law has kicked my butt a few times before!
I try to make sure that his law isn't part of my way of life, by using another anecdote:
"A ounce of prevention is worth a pound of cure."

To that end, I say carry something that you can hotwire the O/D with, in case 'ol Murphy applies "The Law".

Mark.