[Mk2] [Turbo] ECU-IG fuse keep blowing

[MR2allan]

Right - the following has happened... 1991 MR2 Turbo.

My alternator stopped charging. so I replaced it.
Still no charge, so I did a search on the internet and found that the ALT Connector is supposed to have 12V+ on all three points when IGN is on.

Disconnected ALT connector, tested it and BLACK/yellow wire had 0V.

Found the ECU-IG fuse. It was dead.




ALT connector is disconnected

Replaced ECU-IG fuse - turned IGN ON and boom, fuse blown.

Did more internet search and disconnected 'Reverse Light Switch' on gearbox.

IGN ON and boom, fuse blown.

Disconnected intercooler fan

IGN ON and boom, fuse blown.


Anyone know what else I can do to find out why ECU-IG keeps dying..?

[MR2allan]

Well, this one was tricky.

The Black wire with the yellow stripe on it is not something you want to get a short circuit in.

There has to be a short circuit in the loom somewhere.

I disconnected the following

ABS ECU behind the glovebox,
COOLER control box thingy in the trunk,
alternator,
reverse light switch on gearbox,
intercooler fan in engine room
auto antenna in the trunk.

ECU-IG still went to ground.


I ended up connecting a new wire to the black/yellow wire on the alternator, put a fuse on it with a bracket and stuck that in the ECU-IG slot.

The ABS ECU is still out, but I figure I can use the ACC or something and do the same thing with that. Car breaks fine without it aswell.

Looks like the car will do fine without the rest. Who needs cooling fans.. Cooling fans are for pu**ies.