Automotive Air Conditioning Information Forum (Archives)

Provided by

We've updated our forums!
Click here to visit the new forum

Archive Home

Search Auto AC Forum Archives

AC Fuse keeps blowing

mikeshannon on Mon October 24, 2011 4:43 AM User is offlineView users profile

Year: 2000
Make: Isuzu
Model: Trooper
Engine Size: 3.7
Country of Origin: Japan

My AC fuse keeps blowing and I can't seem to figure out the problem. I am "pretty sure" it's not the AC compressor unit or the fan blower. Is there another blower to circulate the air within the truck when the AC unit or fan blower is not on? The fuse will still blow after several seconds even though both units are off (AC & Fan). Thanks for any advice or tips.


TRB on Mon October 24, 2011 3:01 PM User is offlineView users profile

One blower setup on this vehicle. If you can run the blower and not pop the fuse in heat/vent only mode. You have an issue with a/c circuit. Be it compressor or something else. If you try and run the heater/defrost mode you turn on the a/c in many cases.


When considering your next auto A/C purchase, please consider the site that supports you:

mikeshannon on Mon October 24, 2011 11:17 PM User is offlineView users profile

Ok, let me try a few other tests. Thank you for responding.


mikeshannon on Tue October 25, 2011 5:50 AM User is offlineView users profile

Well, unfortunately the fuse (10amp) is now blowing without the ac or fan coming on. Yesterday, I was able to run it for 30 or so seconds, before the fuse blew. Now, nothing (ac/blower/lights on dash for air flow) is working;-((

mk378 on Tue October 25, 2011 9:08 AM User is offline

That's actually good, it's going to make the problem easier to find. If you pull the fuse out and measure ohms from the load side of the fuse holder to ground, is it shorted? If so, you can start unplugging stuff to find what clears the short. Always disconnect the battery before unplugging electrical parts on a modern car.

JACK ADAMS on Tue October 25, 2011 1:45 PM User is offline

Witch fuse is blowing out that is 10amp??

Looks like this is a Clock and Dome light fuse 10amp, witch supplies the a/c Circuit for the control unit. Look at these parts as well, a bad dome light that has shorted out will cause the fuse to blow with out the load of the a/c, blower system.

Edited: Tue October 25, 2011 at 3:53 PM by JACK ADAMS

NickD on Tue October 25, 2011 2:46 PM User is offline

Another scheme is to modify one of your blown fuses with a couple of wires soldered to the two tabs, other end to say a 1157 auto lamp with leads long enough so you can see that bulb. When plugged into the fuse socket that blows fuses, lamp will ignite until you can find the short that can be anywhere.

Didn't say this would be easy, very first thing to put in an empty car shell is the wiring harness. Follow that with a flashlight, straight runs are usually okay, but sharp turns around sharp pieces of metal called wire chafing is where you can find problems, also around hot spots in the engine compartment.

I use a digital readout power supply to test components that displays both voltage and current, For a Trooper, typical blower current is around 16 amperes, clutch coil between 3 and 4, let that sit for awhile, as the coil heats up, current should go down and they is when you see shorts. Having the correct test equipment is necessary, can look all day and be no wiser. Also having a circuit diagram and component placement is a necessity, otherwise you will be spending the rest of your life looking for stuff.

mikeshannon on Mon November 14, 2011 4:42 AM User is offlineView users profile

Dear TRB, MK378, Jack and Nick,

Well, after trying your tips, I sent the truck to a shop down the road. They kept it for 12 days! The good news is they didn't charge me one cent (or yen). They said the fuse blew on them once, but couldn't get it to blow again, and didn't know exactly what caused the proble in the fist place. I want to thank each of you for taking the time out of your day, to try and walk me thru the problem. Best to you all.


Back to Automotive Air Conditioning Forum

We've updated our forums!
Click here to visit the new forum

Archive Home

Copyright © 2016 Arizona Mobile Air Inc.