[Arnold87]

I have a 2016 Corolla. I needed to jumpstart it and stupidly crossed the cables. When I went to get in the car as soon as I open the door the horn went off, that is when I disconnected the cables, hooked them up properly but when I went to try start it there was nothing at all. I changed the 120 amp alt fuse and checked all fuses under the hood and inside and change 4 under the hood and installed a new battery. So now what works is, I have radio, lights, door locks and trunk opens. What doesn’t work, I have no dash activity at all, as far anything in the speedometer area and car just turns over.
Any help would be muchly appreciated.
Thanks

 

[kenny-bob]

Was the key in the ON position when you connected the jumper cables?

If not, did you turn the key to ON with them connected?

If not then you might be able to salvage it, but if so then there are likely ECU(s) damaged from reversed polarity.

 

[Arnold87]

No the key was not on. I had the key in my hand. When I reconnected them the right way I turned the key on but when I didn’t see any dash lights i stopped. I did not try to start it.

 

[XiaoHu]

Check the main battery fuses/fusible links.

 

[rhoderage]

Yes another fuse somewhere

 

[alltoyo]

almost all devices like ecu, radio... are reverse polarity protected so it unlikely you damaged any of those. most likely a fusible link somewhere

 

[Arnold87]

Is there any chance you could tell me where to look for a fusible link? Or what it may look like.

 

[alltoyo]

Is there any chance you could tell me where to look for a fusible link? Or what it may look like.

I don't have experience with that car so I can't tell you where they may be located. Your best bet is to get a repair manual and diagram.

 

[Arnold87]

Thanks. I got the Haynes manual online but no wiring diagrams. I will look on google

 

[alltoyo]

I have bought factory manuals on ebay so you might try there, also I have heard you can get internet access to manuals for a fee but have never done that.

 

[CornBorn]

you can also pay $20 for a one month sub to Alldata DIY and it will have complete factory wiring diagrams for your car

 

[GaryQ]

you can also pay $20 for a one month sub to Alldata DIY and it will have complete factory wiring diagrams for your car

have you tried the NEW version of AlldataDIY? I have a 3 year sub till October for 1 year price to the old site and it sucks.

 

[David314]

Check your local library. Since paper OEM manuals for Toyota have gone away they usually have subscriptions to AllData. You may have to go to the library to get the information and drawings of the electrical system you need.

 

[Hacker_man]

have you tried the NEW version of AlldataDIY? I have a 3 year sub till October for 1 year price to the old site and it sucks.

Why do you say the New version is bad? I have not subsciibed yet.

 

[GaryQ]

Why do you say the New version is bad? I have not subsciibed yet.

No I said the OLD site sucks.
I was asking @CornBorn if he tried the new site since he suggested it to OP

 

[Cibermac]

No the key was not on. I had the key in my hand. When I reconnected them the right way I turned the key on but when I didn’t see any dash lights i stopped. I did not try to start it.

All of my toyotas have had three fuse blocks. One in the engine compartment and the other two under the dash on the drivers side and one near the passenger kick panel.

Find them and check for other burned up fuses.

 

[ken2116]

While critical circuits are likely to be reverse polarity protected, cross connecting also probably generated considerable sparking and rapid current surges that can generate high voltage spikes that might overwhelm over-voltage protections built into semiconductor containing circuits, causing either immediate failure or latent damage leading to failure down the road. Even with the ignition off, some circuits like alarms and those that operate door lights always are "hot" and some others are "on" for the purpose of detecting various activities, and they could be affected.

But first, keep looking for additional fuses and links, and even blown wires and PC board traces.

 

[MoparMarq]

Fusible link is usually in the junction box under the hood. Hard to say on that year/model, but they typically look like a very large (thumb-size, approx.) plug-in fuse. Sometimes they are screwed in to the junction block with two, usually, 8 mm head bolts. The underside of the junction box cover should have a diagram with the labels of all the fuses/fusible links on it. That 's where I'd look first.
Pulled the same move on a '80s Toyota years ago, the fusible link in the underhood junction box melted. Fortunately no other damage.

 

[Arnold87]

Thanks everyone for the help. it ended up being an ignition fuse in the engine bay that i thought i had checked but apparently missed. eventually found it and car runs, no serious damage.

 

[75aces]

Fuse is doing its job. Prevented electrical mayhem. Good job.