Can't seem to narrow this down, maybe you guys can lend a hand.

 

The car is a 93 Legacy AWD Auto.

It drains the battery if left unattended. Runs the coolant fan on the drivers side continuously.

 

When you start the car stone cold, the drivers cooling fan runs, and the temp gauge immediately goes to the normal position. Drive it a bit and the gauge goes to the top quite rapidly.

 

Tried draining the coolant, it had stop leak chunks in it but was otherwise normal green coolant. Installed a known good used gauge sensor and the coolant temp sensor for the computer while I was in there with a brand new unit.

 

No change.

ECU?

 

when you say unattended, do you mean with the key "On" and running? or just "off" and sitting there?

 

Maybe the ECU is still trying to send power to the fans even after no power??

 

 

edit: by no power i mean with the key off..

 

 

 

-Justin

Edited June 11, 201213 yr by crazyman03

You have a short someplace. What happens if you unplug the engine coolant sensor (for the gauge). Can be a cooling fan relay stuck. Could be a few things.

Where I am lost, but also maybe found, is that nothing but the gauge is controlled by the one sender, and the computer and sensors use the other? Right?

ECU?

 

when you say unattended, do you mean with the key "On" and running? or just "off" and sitting there?

 

Maybe the ECU is still trying to send power to the fans even after no power??

 

 

edit: by no power i mean with the key off..

 

 

 

-Justin

 

Off and sitting there. I have been pulling the main fusible link to keep it from draining the battery while it sits.

This is an OBDI so i will defer to anyone else on this one, BUT it can be either one or two sensors, or even three (gauge engeine temp for puter and rad fan switch). I will let someone else answer. It is possible the ECU is the issue, BUT lets rule out an external short first otherwise you may damage an ECU.

At first glance it sounds like a bad ECU, but the gauge makes no sense. The ECT varies resistance with temperature, less resistance means higher temp right? (or is it the other way?)

Either way, gauge wire is shorted? Possibly to the ECU reference wire?

Why the fan is staying on with key off, fried ECU?

I'd start pulling fuses one at a time to see what circuits the fan issue can be narrowed down to. Check for continuity between the ECU wiring and gauge wiring.