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Roy
Roy, import/domestic specialest
Category: Lexus
Satisfied Customers: 4635
Experience:  ASE master tech for 40 years
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What fries when battery is hookek up backwards

Customer Question

what fries when battery is hookek up backwards
Submitted: 4 months ago.
Category: Lexus
Expert:  Roy replied 4 months ago.

good evening my name is ***** ***** I will assist

the main fuse should blow but before it does, the short sends a surge that can burn up the ecm, cluster and any other module in the car. start with checking all the fuses with a test light for power on both sides with the key on. hopefully not much damage is done

Roy

Customer: replied 4 months ago.
I hook up to + termamal it gets hot, how can I use codes with key on,i know which holes to cross
Expert:  Roy replied 4 months ago.

I would not gp there yet until you confirm all the fuses.

does the check engine light come on with key on??

does it run now??

what does not work??

it is an old obd 1 system and wont give much info anyway

Roy

Customer: replied 4 months ago.
cant axcess code reader ,when I hook the second wire to + to lite instruments dash lights terminal gets hot slowly.
Expert:  Roy replied 4 months ago.

can you please answer my questions???

Customer: replied 4 months ago.
it did run before I hooked up wrong.two wires hook to + terminal when wire to fuse box with 125 amp.fuse is touched to + dash lights all come on does not short fuse but starts to get hot.engine lite does not com on with key .added gas but was out of gas.
Expert:  Roy replied 4 months ago.

you need to replace the main fuse first before anything. once that is replaced, then you need to see what works and does not

Roy

Customer: replied 4 months ago.
hi roy this is stan the car does not start. the fuses appear to be good in the main box under the hood. but when you connect the main hot wire that feeds the main fuses under hood it gets to hot to hold
Customer: replied 4 months ago.
it does not blow any fuses though
Customer: replied 4 months ago.
no dash lights or gauges work unless it is hooked up
Customer: replied 4 months ago.
check engine light does not come on it does not start everything unless you power up the ome lead to the fuse box
Customer: replied 4 months ago.
ok it did run until the main positive and negative wires got hooked up in reverse. positive to negative and negative to positive
Customer: replied 4 months ago.
Would that make the main wire get hot if main fuse is bad
Customer: replied 4 months ago.
this is stan again I just tried to test the first part of the fuse box where the main hot lead go in and I think that there is an issue there. so we will check that out and if it doesn't work then I will get back in touch thank you very much for your help. you did a good job. we need to do more testing like you said before we can give you the proper answers. thanks again stan
Expert:  Roy replied 4 months ago.

ok

please dont forget to rate me as it is the only way I get paid for my efforts

Roy

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