Been lurking a long time, just started posting, apparently not enough to start a new thread...

Have an odd electrical issue - part of which OP mentioned I'm trying to diagnose

Did an LED light swap in the dash - backlight only as I've heard swapping the 74s can cause issues. D & L were also out so I replaced with one bulbs from junkyard.

Now I have 2 sets of issues:

Dimmer off - ECT flashes when turn signals are used (as does whatever gear I'm in)

Dimmer on - turn signal indicates wrong direction on cluster, ECT & GEAR flashes, R flashes & engine revs oddly?

Hoping it's a bad ground somewhere but new to molding & wrenching & wondering if anyone might know where to start poking around to resolve.

Thanks!

These can be a pain. I'd start by putting back the original bulbs and see if the problem goes away, while looking carefully at everything you did.

You probably have a damaged flex circuit board on the back of your gauge cluster. When mine when bad, the reverse light would flash with the left turn signal and I would get a CEL for the gear position indicator. Sounds kinda similar (otherwise unrelated systems interacting - they only come close on the gauge cluster).

-Charlie

Thanks, Charlie. is that a swap of the whole instrument cluster? That's where I was leaning after having a buddy over & spending 3-4 hours wiggling, unplugging, retesting & such...

I can't just pull the flex circuit off, can I? Only question/issue I'd have if I have to replace the cluster is the Odometer - I'm guessing I'd just have to find the chip, unsolder & resolder...

it's an 02 SR5 - I believe the 00 cluster is slightly different - do you know if an 01 is the same? Just trying to see if I can find one at a junkyard rather than paying full to have someone else have pulled it...

thanks again!

I answered in the other thread, but that part is available separately, no problem. You can see the process in my build thread, linked in my signature or here:

Phattyduck's '99 4WD swap

-Charlie

thanks, guys - it doesn't seem to be impacting drivability so I might just keep checking pick n pull inventory to see if I can't pick up the whole cluster for like $25, it's $100 less than they're asking used via a toyo parts store (used) & 1/2 of what just the pcb is from a stealership. hopefully an 01 or 02 pops up soon so I can give it a whirl - if it doesn't fix it I'm only out $25 & have replacement bulbs forever ;)

Were you able to solve this problem?