Can't fire up. Buzzing from the relay, lamps blinkin- HELP

[Red]

"That's why I'm asking... is it only "option" in my car or AE86 has something similiar. "
The AE86 has no fuses hanging on wires like that, and no fuses up by the air intake. There's a connection to the airflow sensor in the intake can, and other wiring, but offhand...I have no idea how that relates to an AE82.

"There is a lot of resistance beetwen ECU ground and the body. "
There shouldn't be. The ECU should be screwed/bolted to the body and effectively "at" ground.

"To be sure I've checked the ground of connector from ventilation, and it had no resistance to the body at all. " I take it you mean, from the fan motor to ground there is nearly no resistance, but from the ECU there is high resistance? That could screw up the ECU, sure. You would need to find out why that section of the body wasn't bonded properly, and probably run a ground braid (braided tinned flat ground cable) to the engine block or another good ground in the meantime.

"I mean the bulb burned and the bulb doesn't work... " Right. That happens with light bulbs sometimes, they blow out. That's why we are all supposed to look at the dashboard--every time we start the car--to see if any of the idiot lights have burned out.

"they wouldn't burn out. " Light bulbs burn out! Sometimes, even when they are fairly new. That's just what happens with delicate little wires bouncing around in a harsh environment, made by the cheapest bidder.

It just means you have to take out the instrument cluster and replace the bulb. And, considering how much effort it takes to get in there, I'd replace ALL the bulbs at the same time. They shouldn't "need" replacing, but after 20 years they just might, and who wants to pull that cluster a second time?<G>