wiring issue with 2001 tacoma

A couple weird wiring issues are going on with my 01 tacoma I just bought.

My trip Odometer resets every time I turn the truck off.

My automatic door locks only work when the key is in the "on" position.

Also for my head unit, the memory 12v switch doesn't work, so I had to splice that wire into the switch wire for my radio to work. but the memory resets every time I turn the truck off.

I'm not super knowledgeable with wiring so any help is much appreciated.

The truck is a 2001 Tacoma Extended cab sr5

 

Dome light work?

 

I've checked all fuses

 

The dome light only works when the key is on. The key chime also doesn't work when the key is in off position.

 

Yup I'm lost on what to do, the only thing I can think of is there is a part of the wiring harness that is shorting out somewhere.....

 

Check all the fuses under dash and under hood.

 

PM'd you

 

Not sure what you’re talking about with your head unit but have you tried removing it to see if that is causing any issuing.

Maybe a bad battery? When was the last time you had it checked or replaced?

Checked your fuses under your hood and inside your truck?

 

Replaced battery last week. I also just put the head unit in.

 

Before your new battery or head unit was everything working normal?

You’re probably right but it’s worth checking and taking it out of the equation.

 

no none of it has been working since I've owned the truck which is about a month

 

Sounds like your truck is not getting any power at all while off. Your power locks, ODO, and dome lights are suppose to work without needing the key inserted. Electrical problems are hard, could be vary simple, but finding it is the trick. Unfortunately troubleshooting electrical problems on the internet is just as bad.

If you don’t get any other suggestions on here that are already listed I would take it to the dealer. It’s going to be at least $150-200 for the diagnostic but might be worth it.

 

The 15A Dome Fuse looks to be tied to just about everything you have mentioned that is not working correctly. Like it is loosing power. Maybe it’s tied to the ignition switch some how?

I’m not the best at reading wiring diagrams. But if the 15A Dome is never switched and is supposed to have constant power. I would take a look there for an issue.

Maybe some one with a little more knowledge can help you out.

 

Did you check the PM I sent you? scroll up to the top and look for red dot.

 

The Dome light circuit/fuse seems to be the common link between those systems.

Door locks - ECU has 2 power connections directly from the battery. 1 dome and 1 I assume to send power to the door locks.
Radio - receives constant power from +B which comes from the Dome light. This dome light circuit is also in line with the clock
The Combination meter (Odometer etc..) - receives power from the dome light circuit

All the problems you mention are somehow derived from the Dome light circuit. The dome light circuit in ALL systems you describe is what bypasses the ignition switch directly to the ECU and also splits to the +B constant power to the radio.

I would start with that. Seems that when you turn the ignition in the ON position it may be back-feeding through the ECU to make it work OR you have a bad ground and when the Ignition is in the ON position the Dome light circuit uses the Ignition ground to work.

Just a couple theories. PM me and I can provide wiring schems if needed.

So could be:
1) bad ground
2) bad ECU (if you have someones you can borrow to check since I wouldn't fork out the cash for one until you are 100% certain)
3) bad connection at junctions

I would check the voltage coming from the dome circuit to the ECU when truck is off no key in ignition. Looks to be the L-Y color wire at pin number 4 on the ECU

Wire colors are indicated by an alphabetical code.
B = Black W = White BR = Brown
L = Blue V = Violet SB = Sky Blue
R = Red O = Orange LG = Light Green
P = Pink Y = Yellow GR = Gray
G = Green
The first letter indicates the basic wire color and the
second letter indicates the color of the stripe.
Example: L – Y
L(Blue)-Y(Yellow)

 

@Connor_Rasmor Update?