1997 Mitsubishi Eclipse Heater Relay Fuse Keeps Blowing.

Tiny
BIGTHIN
  • MEMBER
  • 1997 MITSUBISHI ECLIPSE
Electrical problem
1997 Mitsubishi Eclipse 4 cyl Two Wheel Drive 139000 miles

The heater relay fuse blows once I turn the ignition key on. The heater, a/c, and basically all functions of the system does not work. My question is where to begin looking for the short? I've swapped out the heater relay and that did not change anything. Any help would be appreciated.
Sunday, October 26th, 2008 AT 4:18 PM

5 Replies

Tiny
KHLOW2008
  • MECHANIC
  • 41,814 POSTS
Hi Bigthin,

Thank you for the donation.

You should start by unplugging all the components related with the fuse and then with ignition switch on, reinstalling them 1 by 1 till the fuse pops.

If it is Fuse # 11 for the blower motor, then you need to unplug the motor first.

I need to know the specific fuse that is blowing and the full model specifications of your vehicle to get the necessary info on the wiring circuit.

1. Fuse #
2. Turbo or not.
3. Capacity.
Was this
answer
helpful?
Yes
No
Sunday, October 26th, 2008 AT 7:07 PM
Tiny
BIGTHIN
  • MEMBER
  • 3 POSTS
It's the 10 Amp #13 Heater Relay fuse that is blowing when the ignition turns on. I've isolated almost everything, and I found out that when I connect the Automatic Compressor ECM with the ignition on the fuse blows. I've tryed isolating everything associated with the ECM but the fuse still blows. Could the ECM be blowing the fuse? I can't see any damage on the circuit board. It's a 1997 Mits. Eclipse RS 2.0 liter engine. I hope this is enough info for you. Thanks for your help.

Brendan
Was this
answer
helpful?
Yes
No
Monday, October 27th, 2008 AT 11:29 PM
Tiny
KHLOW2008
  • MECHANIC
  • 41,814 POSTS
Hi Brendan,

Ok, I got the fuse and the circuits that uses it.


https://www.2carpros.com/forum/automotive_pictures/192750_Fuse13Dash97Eclipse_1.jpg



Here are a list of items associated with the auto compressor ECM
1. Dual pressure switch
2. A/C switch
3. fin thermo sensor
4. Compressor revolution pickup sensor
5. Defroster switch
6. ECM (Engine)
7. Compressor
8. Condenser fan relay.

If you have not tested any of the above, might as well give it a try. The compressor is the most likely item as it has a higher possibility to cause shorting. However with AC switch unplugged, it should not cause the shorting.

It is possible for the ECM to short internally as there is a ground wire from it.

The data above are for a non turbo automatic, so hope it is the correct vehicle and let me know if you are able to solve the problem.

Good luck.
Was this
answer
helpful?
Yes
No
Tuesday, October 28th, 2008 AT 12:05 PM
Tiny
BIGTHIN
  • MEMBER
  • 3 POSTS
I ended up pulling all the wires out of the Automatic Compressor ECM. I installed only the hot wire and when I installed the ground wire with the engine running it blew the fuse. I found that one of the resistors on the ECM has a direct short going through it. I can't find anything on the internet about replacing the Automatic Comp. ECM. Any ideas and pricing about getting a replacement? Thanks for the help.
Was this
answer
helpful?
Yes
No
Wednesday, October 29th, 2008 AT 12:23 PM
Tiny
KHLOW2008
  • MECHANIC
  • 41,814 POSTS
Hi Bigthin,

Sorry I don't have any info where to source the item.
Since you have isolated the source, you can try replacing the resistor if soldering can be done. The resistor should be availble at electronics parts stores and would not cost you more than a buck each.
Was this
answer
helpful?
Yes
No
Wednesday, October 29th, 2008 AT 1:44 PM

Please login or register to post a reply.

Related Heater Relay Location Content

VIEW MORE