Fuse problem with Emergency Flashers when Van connected

Submitted: Tuesday, Feb 12, 2008 at 09:44
ThreadID: 54497 Views:1817 Replies:3 FollowUps:6
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On our 2002 Mitsibushi Challenger 4WD the turn indicator flashers and Emergency Flashers have worked fine. There is a 10A fuse in the Emergency Flasher circuit.

We have a 18 foot Crusader van with a 7 pin connector plug. Each time we hook our van to the car we do a check that the turn indicator lights and break lights at the rear of the van are working. Normally I check each turn indicator light and find it is OK.

A couple times in the last year I have used the Emergency flasher switch on the car to check both flashers are operating at the same time. Each time I have found within a few days that the 10A fuse for the Emergency flasher in the Challenger has blown and has to be replaced.

My first inclination is to simply use a bigger fuse in the car Emergency Flasher but wonder if this is the most sensible to do.

Can you suggest what tests I can do to simplify identify the cause of the problem. The van is currently in storage and not connected to the car. The van manufacturer is unable to supply a wiring diagram for the van.

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Reply By: DIO - Tuesday, Feb 12, 2008 at 09:49

Tuesday, Feb 12, 2008 at 09:49
Now I'm not 100% sure of this, but I believe the Mitsubishi range has the electrical wiring a little different to many other vehicles. A friend has such a make and he discovered when wiring up for driving lights that the circuit was positive earth and he had to use the earthing connection as the on/off function. Could it be that your van's wiring is just not compatible with the tow vehicle.
AnswerID: 287027

Follow Up By: DIO - Tuesday, Feb 12, 2008 at 09:50

Tuesday, Feb 12, 2008 at 09:50
Sorry forgot to add.....when he tried to activate his newly wired up lights he too kept on blowing fuses until such time he realised what was going on. Good luck with it.
FollowupID: 552254

Follow Up By: MrBitchi (QLD) - Tuesday, Feb 12, 2008 at 10:47

Tuesday, Feb 12, 2008 at 10:47
Dio, they don't have a positive earth system but the wiring is not what you would call "normal". Basically it uses a multiplex system, sorta like the data bus on a computer, where many components share the same wiring at different times. Makes it a bloody nightmare to fault find as the symptoms can easily hide the cause. When I first blew the hazard light fuse on mine the symptoms were the emergency brake warning light, the transmission temperature light and the centre diff lock light all came on at once... Go figure.... ;-(
FollowupID: 552258

Reply By: MrBitchi (QLD) - Tuesday, Feb 12, 2008 at 10:42

Tuesday, Feb 12, 2008 at 10:42
This is a common problem with late model Pajeros'. The fuse blows when a trailer is connected and the central locking is activated, which flashes the emergency lights and promptly blows the fuse.

Simply install a 15 amp fuse and it'll never happen again. Some have wired a relay into the hazard light circuit but personally I think that's overkill. I replaced my fuse 4 years ago and have had no further problems.
AnswerID: 287033

Follow Up By: Mike Harding - Tuesday, Feb 12, 2008 at 11:04

Tuesday, Feb 12, 2008 at 11:04
Sounds a reasonable solution to me. iirc flasher lamps are 21 watts each so 6 of them will total 126W which equates to 10.5 amps but it's worse than this because when a filament lamp is switched on from cold the short term (quarter second or so) current is probably twice the current when the lamp is hot. Given that hazard lights are regularly being switched on from cold I'm not surprised the fuse blows.

Mike Harding
FollowupID: 552261

Follow Up By: Member - nrb1748 (VIC) - Tuesday, Feb 12, 2008 at 16:54

Tuesday, Feb 12, 2008 at 16:54
And maybe 2 more lights in a bullbar???

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FollowupID: 552293

Reply By: BMKal - Wednesday, Feb 13, 2008 at 03:30

Wednesday, Feb 13, 2008 at 03:30
Have a slightly similar issue to this with the Landrover. I don't blow fuses, but the Landrover has an indicator light on the dash that is supposed to flash with your indicators when you have a trailer connected - purpose is to let you know that the trailer lights are working. Because I've had a bullbar added which has indicator lights included, the "trailer" indicator light now flashes with the indicators all the time, whether there is a trailer connected or not.

The issues here are identical - too many globes for the original wiring circuit of the vehicle. Your caravan with its extra lights is probably OK when only the indicators are working one side at a time, but with the hazard lights on and all the indicators flashing together, it's simply too much load on the circuit.

The solution is also simple - change some of your indicators, preferably those on the caravan, from filament globes to LED's. They pull a fraction of the power and will reduce the load on the circuit to the point that the problem no longer exists.
AnswerID: 287188

Follow Up By: MrBitchi (QLD) - Wednesday, Feb 13, 2008 at 09:10

Wednesday, Feb 13, 2008 at 09:10
New fuse is cheaper ;-))
FollowupID: 552378

Follow Up By: BMKal - Thursday, Feb 14, 2008 at 04:09

Thursday, Feb 14, 2008 at 04:09
No doubt.

But then I've never believed in increasing the fuse rating above what was originally installed. Mistubishi installed a 10a fuse here for a reason.
FollowupID: 552610

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