Forum Index
Jeep Horizons HomeLinksJeep Horizons Tech Write-upsJeep newsLand useContact

 Watched TopicsWatched Topics   FAQFAQ   SearchSearch   MemberlistMemberlist   UsergroupsUsergroups   RegisterRegister 
 ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in 

1993 Jeep drained battery and smoking ECM (or EMS or ECU)


 
Post new topic   Reply to topic     Forum Index -> Cherokee Forum
View previous topic :: View next topic  
Author Message
NikkiS
Member


Joined: 02 May 2007

PostPosted: Thu May 03, 2007 8:29 am    Post subject: 1993 Jeep drained battery and smoking ECM (or EMS or ECU) Reply with quote

It's a shame but my first post to this forum is one for help.

I've owned my lovely 1993 Cherokee for 6 months now with no problems, until....

A month ago I wa away in a field camping. Arrived on the Friday night, parked up and didn't attempt to move till Sunday. Sunday morning the central locking wouldn't work... turned out the battery had been completely drained of power. This in itself was confusing as no lights (internal/external) had been left on and there had been no problems the night before... except....

The Saturday night I'd gone to manually lock the jeep (because the lock button on the keyfob is broken) when my partner suggested I just use the "lock doors" button inside the passenger door and then lock that one door manually. At his suggestion I did this.... I don't recall ever using this button before.... could this have shorted and caused the battery drain?

Anyway, after discovering the battery was dead we tried to jump start the jeep. At that point smoke starting emerging from the ECM (or ECU or EMS... the electronics management system... I've seen it by so many different acronyms). The kind of smoke that smells fishy / electronic / bad!!

The jeep was recovered back home and later on I tried fully charging the battery and putting it back in the jeep. As soon as both cable were hooked up (just on the terminals, not tightened up) the ECU/EMS/ECM started smoking again.

I'm now at a loss of what to do. I've been told by a jeep dealership that there shouldn't be enough power going to the unit to cause it to smoke.

Any ideas what to check and where to start?

Thanks,
Nikki
Back to top
View user's profile Send private message
JeepinNH
Member


Joined: 13 Sep 2005
Location: New Hampshire

PostPosted: Fri May 04, 2007 9:49 am    Post subject: smoke Reply with quote

Ouch, sounds like something is shorted in the ECM. I would, with the battery out, check resistance between the positive and negative cables. It should be pretty high in Ohms. If it is low then unplug the ECM and see if it goes up. You may want to look for frayed wires around the ECM.
_________________
Mike

Present: 99 Cherokee
Past: 86, 87 Cherokee; 94 Grand Cherokee
Back to top
View user's profile Send private message
NikkiS
Member


Joined: 02 May 2007

PostPosted: Wed May 09, 2007 12:42 am    Post subject: Scorched ECM Reply with quote

I couldn't see any scorched / broken wires leading into the ECM. I took the ECM out and on the underside there is a large scorched patch complete with sticky, slightly melted rubber. The scorched patch seems to be directly underneath the heat sink.

Nikki
Back to top
View user's profile Send private message
NikkiS
Member


Joined: 02 May 2007

PostPosted: Wed May 09, 2007 12:42 am    Post subject: Also.... Reply with quote

.... what I meant to ask is do you think it could just be a problem with the ECM or a problem with a short elsewhere which in turn overloaded the heatsink and caused the burning?

Thanks!!
Back to top
View user's profile Send private message
JeepinNH
Member


Joined: 13 Sep 2005
Location: New Hampshire

PostPosted: Thu May 10, 2007 7:19 pm    Post subject: Reply with quote

It's tough to tell with electronic stuff. It can be a crap shoot.
_________________
Mike

Present: 99 Cherokee
Past: 86, 87 Cherokee; 94 Grand Cherokee
Back to top
View user's profile Send private message
Display posts from previous:   
Post new topic   Reply to topic     Forum Index -> Cherokee Forum All times are GMT - 8 Hours
Page 1 of 1

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum


Visit links4jeeps.com for write-ups, forums and clubs




Jeep®, Wrangler, Cherokee, Liberty and Grand Cherokee are copyrighted and trademarked to Chrysler LLC.
jeephorizons.com is not in any way associated with or endorsed by the Chrysler LLC.
All other content is copyright Jeep Horizons 2004-2008.
Tech write-ups Links Discussion board Land use News Site Map Terms of Use

Powered by phpBB © 2001, 2005 phpBB Group