2000 2wd Electrical Questions

[Irish77060]

Hey all! Since we are all stuck at home, maybe one of you sharpshooters can help with an electrical issue. 2000 4R SR5 2wd

Before the problem, door lock auto open/lock feature would intermittently fail-so I’m thinking BCM and also my old battery. I know a weak battery will cause issues especially with the factory security system.

Issue started when I went out to go to work and turned the key-nothing. Fiddled with they key to see if it was a switch problem (still could be). So I pop the hood and see horrible corrosion on both terminals. And, the wire to the fuse box (8 gauge) attached to the positive post was barely hanging on. In fact, when I fiddled with it it promptly broke off. So, off to the dealer for a new battery. Replaced both clamps and made an extension on the 8 gauge wire to connect it. Good solid connection on the extension.

It didn’t start at first. Then it did. Then it didn’t. Door locks started acting weird again. Wiggled key in slot a bit. Started. Door locks still weird. May or may not work. When I worked at Toyota service back in 2000 I would see these things happen and more often than not it was the switch. But after checking the threads everyone thinks BCM.

My livelihood depends on this4runner, but I don’t trust it right now. Thoughts? I’m great at mechanical but SUCK at electrical.
Thanks.

 

[plcfcng]

As bad as you stated the cables are and you only replaced the cables make sure the cables themselves are in good shape. Any connections I would not just do a crimp just asking from problems down the road. While i don't have a specific to your problem answer I would insure all the grounds are clean and tight first and you could do a voltage drop test and take a reading from the charging circuit in addition.

 

[Irish77060]

Thanks. I did cut them back over an inch to find good copper. Filed the ground points to shined metal.

 

[Irish77060]

So I retraced my battery cable paths, and insured all clean and connected. Inserted key, all dash lights on, key fob worked with ALL locks as it should. It cranked and warmed to running temp. I shut it down. It would not start again, no turnover at all and dash lights significantly dimmer. Door locks not functioning. Went back to the battery and the Positive terminal was so hot it burned my hand. Disconnected it. Anyone?

 

[Irish77060]

And I realize that resistance from a bad connection will cause the heat. Unless I change the fuse box for a new wire or the front engine harness, not sure if it is a corrective measure, I’m at a loss. Not a lot of $$$ to put in this.

 

[TheDurk]

Bolt-on terminals?? Trash those. New cables or pro-done crimp or solder.

 

[Irish77060]

Criticizing what I’m doing is not helping. Bolt on is all I have right now. They are new and tight with ultra clean connections and should not cause an problem while I am diagnosing this issue. New terminals are part of the front harness and that portion of it is $283.00 ( Cheapest I’ve found). If anyone has a real idea for me to use let me know. Thank you.

 

[plcfcng]

Reading earlier you said the heat caused resistance it's the other way around the resistance caused the heat. Without the resistance there would be no heat so where there is heat address that part. If all you have are bolt on terminals and there is heat there make sure it's clean thing another thing you can do is get come copper anti cease (it's like the gray stuff but it uses copper.) Make sure the post to battery are clean well mated.

Remember that all the wires electrical parts have been engineered if there are problems in the engineering it would be widely addressed here. So If you find any kind of burnt wires or heat address them. I am a little confused what are the problems that your still having.:dancin:

 

[TheDurk]

Criticizing what I’m doing is not helping. Bolt on is all I have right now. They are new and tight with ultra clean connections and should not cause an problem while I am diagnosing this issue. New terminals are part of the front harness and that portion of it is $283.00 ( Cheapest I’ve found). If anyone has a real idea for me to use let me know. Thank you.

You are using bolt-on terminals and they are getting hot. Why do you think I guessed you were using bolt-ons? I'm sure others will suggest lots of 'real ideas'. They just won't fix your problem.

 

[T.Tech]

Possible starter failure causing too much amperage draw but not enough to blow the fuse. Lights on dash become dim due to starter attempting to turn engine over. Door lock issue seems weird though.