SeaDoo challenger 2005 Hooked up the battery backwards

[Scar1808]

Owner of a challenger 2005 and did hook up the battery backward(I’m a dumb A I know already)

Now I’m trying to figure why it does not beep anymore when I plug the DESS

(The 5 amp fuse was blown, replaced it and each time I plug the DESS it blows)

When I plug the DESS the rpm flicker a bit but no beep —Accessories seems to be working.

any thoughts idea on where I should start looking?

ty guys

 

[Scar1808]

Is there a Diode on this unit? If so is it part of the MPEM?


Boat repair shop does not seems to be able to find the problem

 

[turbosl2]

I would let the MPEMs power down overnight without any battery connected. Check ALL fuses on the MPEM. Reinstall the battery the correct way and see what happens. If this continues i hate to say it but the MPEM may have a fried resistor. I hate to trip to that because i actually did the same thing in one of my PWCs a few years back. If i recall letting all capacitors power down (could touch the positive and negative leads together for 10 seconds so you dont have to wait...WITHOUT THE BATTERY HOOKED UP.

I suspect capacitors are charged in reverse polarity. Give that a try and report back.

 

[swaskey]

My limited understanding of the MPEM/ECU controllers is that their power input side can be damaged rather quickly when powered in reverse polarity.

Blowing fuses that quickly (Based on your statement, I assume within a couple moments of placing key on post) indicates a direct short, somewhere. If everything was working as expected prior to reversing the polarity, it's unlikely a harness or connection failed at the same time to be the root cause. The DESS post could go bad, and aren't expensive, but there's not much to short inside there (and is unlikely to take damage from reversed polarity at the battery).

This may be premature, but your symptoms sound like a faulty MPEM. I'd love to get in there with a meter and schematic.

To double-check, which fuse exactly is poping?
Do you have access to a Candoo?

 

[turbosl2]

Swaskey is correct and similar to what I said above. However the circuits inside the mpem could be charged in reverse polarity if the mpem contains capacitors. I don’t know for sure. There are people that repair them for a few hundred dollars. No need to spend thousands and a reprogram.
Try discharging like I mentioned above before you send the mpem out for repair. I totally did this same mistake since my pwc battery was buried in the hull of my 04 XPdi… I couldn’t see which side was positive. Blew fuses just like this until I touched the leads together and let it sit. Then all was good!

External bench test if you need it. May not be your exact model but same principle applies.

https://www.jetskiplus.com/nonwiredmpemtest

 

[Scar1808]

My limited understanding of the MPEM/ECU controllers is that their power input side can be damaged rather quickly when powered in reverse polarity.

Blowing fuses that quickly (Based on your statement, I assume within a couple moments of placing key on post) indicates a direct short, somewhere. If everything was working as expected prior to reversing the polarity, it's unlikely a harness or connection failed at the same time to be the root cause. The DESS post could go bad, and aren't expensive, but there's not much to short inside there (and is unlikely to take damage from reversed polarity at the battery).

This may be premature, but your symptoms sound like a faulty MPEM. I'd love to get in there with a meter and schematic.

To double-check, which fuse exactly is poping?
Do you have access to a Candoo?

And don’t have a direct access to candoo unfortunately

And yes everything was working like normal last season

 

[Scar1808]

Btw thx for the replies guys...I will be taking my boat back this week cause the repair shop is too busy To check it (They will only start working on it in 3 weeks)and I need that thing working ASAP

I will run some more checks on my hand