Cooling fan causing major voltage drop....

From Tune Ups to Oil Changes, maintenance related

Moderator: toayoztan

Cooling fan causing major voltage drop....

Postby Rallly » Tue May 30, 2017 7:33 am

So I tested the Alt, charges fine then I thought it was a bad battery, changed it to new. Still getting an intermittent flickering battery light. Turns out when the cooling fan kicks on it draws so much voltage bringing it down to low 12's ... once fan is off alt charges back up to 13.8-14.3. What should I look for? Would it be a short or bad fan relay?
Members don't see the above ad. Register now - it's free!
Rallly
Club Member
 
Posts: 185
Joined: Wed Jul 29, 2015 12:31 am

Re: Cooling fan causing major voltage drop....

Postby aus jd 2703 » Wed May 31, 2017 1:57 am

Me personally would check the fans current draw if possible.
Otherwise it's likely a dead alternator.
What size fuse is in the fan ?

Btw alternators on all celicas are 60+amp so I wouldn't think a 30amo fan (which stock is less than) would drain the battery
aus jd 2703
Established Member
 
Posts: 1089
Joined: Wed Apr 30, 2008 12:02 am

Re: Cooling fan causing major voltage drop....

Postby Rallly » Wed May 31, 2017 7:24 am

Wouldnt a dead alternator stop charging bat all together?
Rallly
Club Member
 
Posts: 185
Joined: Wed Jul 29, 2015 12:31 am

Re: Cooling fan causing major voltage drop....

Postby aus jd 2703 » Wed May 31, 2017 7:40 am

Dieing alternator maybe
aus jd 2703
Established Member
 
Posts: 1089
Joined: Wed Apr 30, 2008 12:02 am

Re: Cooling fan causing major voltage drop....

Postby mx6er2587 » Wed May 31, 2017 12:21 pm

yeah, I've seen dying alternators not put out as much current as they're supposed to.
mx6er2587
Established Member
 
Posts: 1162
Joined: Sun Jan 27, 2008 12:08 am
Location: Pittsburgh PA

Re: Cooling fan causing major voltage drop....

Postby Rallly » Wed May 31, 2017 3:34 pm

mx6er2587 wrote:yeah, I've seen dying alternators not put out as much current as they're supposed to.


Thanks I'll change it out then :)
Rallly
Club Member
 
Posts: 185
Joined: Wed Jul 29, 2015 12:31 am

Re: Cooling fan causing major voltage drop....

Postby alltracman78 » Thu Jun 01, 2017 1:22 am

Before you change it out you might want to check some other circuits to make sure you don't waste your money.

Turn on the headlights, defroster, rear defroster and put the windows down at the same time. If you have power problems then it's probably the alt. If not, take a look at the fan circuit.
Image
User avatar
alltracman78
GTFour God
 
Posts: 4675
Joined: Mon Aug 09, 2004 9:04 am
Location: Ma

Re: Cooling fan causing major voltage drop....

Postby Rallly » Thu Jun 01, 2017 7:04 am

alltracman78 wrote:Before you change it out you might want to check some other circuits to make sure you don't waste your money.

Turn on the headlights, defroster, rear defroster and put the windows down at the same time. If you have power problems then it's probably the alt. If not, take a look at the fan circuit.



I did similar, put high beams on, interior fan, rear defroster , radio bat was holding at 13.9. Once the cooling fan turned on it dropped to 12.4 and trickles down until fan shuts off. Seems the alt just can't keep up. It's a brand new battery btw.
Rallly
Club Member
 
Posts: 185
Joined: Wed Jul 29, 2015 12:31 am

Re: Cooling fan causing major voltage drop....

Postby aus jd 2703 » Thu Jun 01, 2017 7:07 am

Na that sounds like a short in the cooling fan system.
aus jd 2703
Established Member
 
Posts: 1089
Joined: Wed Apr 30, 2008 12:02 am

Re: Cooling fan causing major voltage drop....

Postby Rallly » Thu Jun 01, 2017 7:09 am

aus jd 2703 wrote:Na that sounds like a short in the cooling fan system.


Hmmmm. So should I start looking for burnt wires and clean all contact points?
Rallly
Club Member
 
Posts: 185
Joined: Wed Jul 29, 2015 12:31 am

Re: Cooling fan causing major voltage drop....

Postby aus jd 2703 » Thu Jun 01, 2017 7:10 am

Look for a hot spot or melting. Must be a decent short to drop that mug voltage
aus jd 2703
Established Member
 
Posts: 1089
Joined: Wed Apr 30, 2008 12:02 am

Re: Cooling fan causing major voltage drop....

Postby Rallly » Thu Jun 01, 2017 7:11 am

K thank you!
Rallly
Club Member
 
Posts: 185
Joined: Wed Jul 29, 2015 12:31 am


Return to General Maintenance and Repair

Who is online

Users browsing this forum: No registered users and 3 guests