# Jumping a battery backwards **URL:** \ **Category:** Maintenance/Repairs\ **Created:** [August 16, 2008, 6:43pm UTC](https://community.cartalk.com/t/jumping-a-battery-backwards/18264 "2008-08-16T18:43:29Z")\ **Posts on this page:** 18\ **Page:** 1
**Author:** ![wburrows2](https://avatars.discourse-cdn.com/v4/letter/w/7ea924/32.png) [@wburrows2](https://community.cartalk.com/u/wburrows2)\ **Post date:** [August 16, 2008, 6:43pm UTC](https://community.cartalk.com/t/jumping-a-battery-backwards/18264/1 "2008-08-16T18:43:29Z")
A dealership tells me the problem with my 2004 Mazda 3 is someone jumped the battery backwards and destroyed all the “fuseable links” in the harness requiring complete replacement of all the wiring. But, before taking it in, I determined that only one 10 amp fuse was blown and all the relays were fine. How is that possible? ---
**Author:** ![hellokit](https://avatars.discourse-cdn.com/v4/letter/h/6a8cbe/32.png) [@hellokit](https://community.cartalk.com/u/hellokit)\ **Post date:** [August 16, 2008, 6:53pm UTC](https://community.cartalk.com/t/jumping-a-battery-backwards/18264/2 "2008-08-16T18:53:04Z")
Evidently, the dealership is using an unregulated GUESS-O-METER. If fusible links are blown, an independent shop can splice new fusible links into the wires. All the wires (wire harness) DO NOT need to be replaced. Save a mortgage payment…go to an independent shop/mechanic. ---
**Author:** ![Joseph\_E\_Meehan](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/joseph_e_meehan/32/21_2.png) [@Joseph\_E\_Meehan](https://community.cartalk.com/u/Joseph_E_Meehan)\ **Post date:** [August 16, 2008, 6:54pm UTC](https://community.cartalk.com/t/jumping-a-battery-backwards/18264/3 "2008-08-16T18:54:52Z")
What the dealer said is possible. However the damage would have been done at the time the battery was jumped. It would not have shown up six months later. The question you did not answer is: Was the car improperly jumped? From your message I would guess it was. The fuseable links they are talking about are not exactly fuses and don’t look like fuses. Sorry. ---
**Author:** ![oblivion](https://avatars.discourse-cdn.com/v4/letter/o/3ab097/32.png) [@oblivion](https://community.cartalk.com/u/oblivion)\ **Post date:** [August 18, 2008, 11:24pm UTC](https://community.cartalk.com/t/jumping-a-battery-backwards/18264/4 "2008-08-18T23:24:20Z")
Would be useful to know what problem you’re having, and what the symptoms are, as well as if you have any awareness of whether there’s a possibility it was ‘jumped backwards’ Fusible links can be replaced. It’s extremely doubtful that the entire wiring harness would need to be replaced. However, if jumper cables were really connected backwards, you may have damage to the car’s computer(s) and other electronics. Again, would really be useful if you could mention what the car is doing. (or not doing) ---
**Author:** ![vwfueldoor](https://avatars.discourse-cdn.com/v4/letter/v/e95f7d/32.png) [@vwfueldoor](https://community.cartalk.com/u/vwfueldoor)\ **Post date:** [August 19, 2008, 12:35am UTC](https://community.cartalk.com/t/jumping-a-battery-backwards/18264/5 "2008-08-19T00:35:52Z")
one fuse would blow,and only one fuse. the 100-150amp alternator fuse. 10amp fuse?. NOT! ---
**Author:** ![Tanice\_Dene](https://avatars.discourse-cdn.com/v4/letter/t/ecccb3/32.png) [@Tanice\_Dene](https://community.cartalk.com/u/Tanice_Dene)\ **Post date:** [October 7, 2019, 9:36pm UTC](https://community.cartalk.com/t/jumping-a-battery-backwards/18264/6 "2019-10-07T21:36:49Z")
I lost the key to my 2015 nissan rogue and had absolutely no issues before that. After being told I needed a new computer(bcm) I also had to get a brand new battery and (ecm) computer because the dealership said the key still wasnt responding and that my car was jumped backwards. After $2000 in repairs my air is now not working and my back up camera. They are trying to tell me the car keeps reading communication codes and I may have another big issue which may be replacing the harness. What do I do now? ---
**Author:** ![Rod-Knox](https://avatars.discourse-cdn.com/v4/letter/r/a183cd/32.png) [@Rod-Knox](https://community.cartalk.com/u/Rod-Knox)\ **Post date:** [October 7, 2019, 11:09pm UTC](https://community.cartalk.com/t/jumping-a-battery-backwards/18264/7 "2019-10-07T23:09:15Z")
It has been my experience that if the battery polarity is reversed for some reason with the key off the main fusible link will always burn as @vwfueldoor mentioned. If the key is on though a lot of damage can and usually will occur. Control modules, various relays and a great many fuses will usually be burned and even wiring harnesses can be trashed. A good independent shop that specializes in electrical issues might solve the problems quicker and cheaper than whoever is working on the car now. ---
**Author:** ![keith](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/keith/32/5518_2.png) [@keith](https://community.cartalk.com/u/keith)\ **Post date:** [October 8, 2019, 6:59pm UTC](https://community.cartalk.com/t/jumping-a-battery-backwards/18264/8 "2019-10-08T18:59:13Z")
If you had no problems before loosing your key and the problems presented themselves immediately after you got the replacement key, the key is the problem and your dealer should be put out of business. If you jumped or had someone jump off your car and they hooked the cables up backwards, and the problems occurred immediately after that, then that is the cause of your problems. Now if you don’t remember anyone using jumper cables on your vehicle, then maybe the dealer used jumper cables for some reason and that is how they know the cables were hooked up backwards and they should be paying for the repairs, not you. ---
**Author:** ![shadowfax](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/shadowfax/32/13026_2.png) [@shadowfax](https://community.cartalk.com/u/shadowfax)\ **Post date:** [October 8, 2019, 7:05pm UTC](https://community.cartalk.com/t/jumping-a-battery-backwards/18264/9 "2019-10-08T19:05:47Z")
> [@Tanice\_Dene](#): > > What do I do now? Tell them to put the car back the way it was when you brought it in, and to stop lying to you. You didn’t need to replace the computer just because you lost a key. Once they did that, they screwed up the work and now want to blame “jumping it backwards” instead of “we broke something that we didn’t need to mess with in the first place.” ---
**Author:** ![Barkydog](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/barkydog/32/2470_2.png) [@Barkydog](https://community.cartalk.com/u/Barkydog)\ **Post date:** [October 8, 2019, 7:22pm UTC](https://community.cartalk.com/t/jumping-a-battery-backwards/18264/10 "2019-10-08T19:22:15Z")
We had a KIA, I went to get an extra fob made, sorry only 2 fobs, you loose one it will be $300 to program 2 new ones. ---
**Author:** ![Drkrachel](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/drkrachel/32/17826_2.png) [@Drkrachel](https://community.cartalk.com/u/Drkrachel)\ **Post date:** [October 8, 2019, 7:25pm UTC](https://community.cartalk.com/t/jumping-a-battery-backwards/18264/11 "2019-10-08T19:25:31Z")
Had the neighbor jump my truck once and he hooked it up backwards. Just blew a fuse. That is the whole point of fuses is to protect electronic components. Anytime something electric goes out that is the first place to look for the problem. ---
**Author:** ![shadowfax](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/shadowfax/32/13026_2.png) [@shadowfax](https://community.cartalk.com/u/shadowfax)\ **Post date:** [October 8, 2019, 9:05pm UTC](https://community.cartalk.com/t/jumping-a-battery-backwards/18264/12 "2019-10-08T21:05:05Z")
Sometimes the fuses don’t blow fast enough to prevent other damage. But from OP’s story, what happened here is that the dealership is making up a story about how someone jumped the car backwards. If someone had jumped the car backwards and blown the main fuse, then OP would not have been able to start the car immediately after that happened. Instead the dealership would have (second)OP believe that someone jumped the car backwards, it blew fuses but kept driving just fine and working perfectly until OP lost her key, at which point the blown fuses actually started acting like blown fuses. As the Brothers would say, booo-ooo-ooo-gus! ---
**Author:** ![NYBo](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/nybo/32/17281_2.png) [@NYBo](https://community.cartalk.com/u/NYBo)\ **Post date:** [October 9, 2019, 12:42am UTC](https://community.cartalk.com/t/jumping-a-battery-backwards/18264/13 "2019-10-09T00:42:36Z")
Did any of you notice the starting date for this thread? @Tanice_Dene, your problem is unrelated to the original topic. You should start your own thread. ![image](https://global.discourse-cdn.com/cartalk/original/3X/9/4/9430fd39a53c407b0484f6787816012d9c3a91c7.jpeg) ---
**Author:** ![Drkrachel](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/drkrachel/32/17826_2.png) [@Drkrachel](https://community.cartalk.com/u/Drkrachel)\ **Post date:** [October 9, 2019, 2:40am UTC](https://community.cartalk.com/t/jumping-a-battery-backwards/18264/14 "2019-10-09T02:40:15Z")
> [@NYBo](#): > > Did any of you notice the starting date for this thread? Wait we should read the whole thing??? No I did not lol ---
**Author:** ![bing](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/bing/32/4619_2.png) [@bing](https://community.cartalk.com/u/bing)\ **Post date:** [October 9, 2019, 5:29am UTC](https://community.cartalk.com/t/jumping-a-battery-backwards/18264/15 "2019-10-09T05:29:36Z")
I knew it was old because at least one of the posters is dead now (rest his soul). Good to see their posts again though. ---
**Author:** ![cdaquila](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/cdaquila/32/18089_2.png) [@cdaquila](https://community.cartalk.com/u/cdaquila)\ **Post date:** [October 9, 2019, 5:51am UTC](https://community.cartalk.com/t/jumping-a-battery-backwards/18264/16 "2019-10-09T05:51:23Z")
Since the same language was used in the old post, it’s understandable she’d post in the old thread as a follow-up. There’s nothing that says she can’t do that because we don’t archive old threads as we did in prior forum incarnations. ---
**Author:** ![Drkrachel](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/drkrachel/32/17826_2.png) [@Drkrachel](https://community.cartalk.com/u/Drkrachel)\ **Post date:** [October 9, 2019, 11:59am UTC](https://community.cartalk.com/t/jumping-a-battery-backwards/18264/17 "2019-10-09T11:59:24Z")
When I seen the post it showed the last reply was a few hours ago, when I viewed the post it started out where the newer posts begin and ofcourse like a few others of us here we didn’t scroll up. But it is along the topic line atleast. ---
**Author:** ![shadowfax](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/shadowfax/32/13026_2.png) [@shadowfax](https://community.cartalk.com/u/shadowfax)\ **Post date:** [October 9, 2019, 1:17pm UTC](https://community.cartalk.com/t/jumping-a-battery-backwards/18264/18 "2019-10-09T13:17:44Z")
As long as the topic is the same, I don’t have a problem with resurrecting old threads for new stuff related to the topic. When you search Google, sometimes that old thread pops up as a result and then the new user just posts there thinking that’s what they should do. No big deal.