Have Toyota Questions? Ask a Mechanic for Answers ASAP
Thank you for allowing me to help you with this concern today and am sorry to hear that this is happening. I will have to ask you a few questions so that I can get a better understanding as to what may be going on with your Sienna.
It looks like we may have more than one problem with this Sienna.
Does the car start now?
They could be shorted due to a bad cell inside the battery. Then again it is not usual to see sparks when connecting jumper cable to the battery.
Do you have an extra car battery or an auto parts store nearby? A new battery should solve this part or the problem.
Now as for the no start thats been going on for some time, when the key was turned, do you remember hearing just one click type noise?
If you are getting sparks from the terminals with no battery connected then the starter itself is doing this. That is the only load between the two. What it sounds like is the starter contacts are fused together. Is this the original starter or an aftermarket one?
I see. Thats' about the life expectancy with these.
Do we need a new starter or can it be repaired?
With this major of an issue, I would not try and have this one rebuilt. I would recommend a new or re manufactured one.
Why did the wires not burn up?
Because of the battery. These wires are designed to carry quite a load, with a weak battery and the fact that the starter still had resistance in it to absorb some of the electrical current.
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