clublexus,

91 LS400

I made a bonehead move today by dropping the battery into the tray 180 degrees off that caused a reverse of the cables , the new car battery had some sparks but the usual at first when connecting a battery but it was too late when I realized I crossed the cables. (my cables are not color coded) so now I have no power in the cabin with the lights,radio,cluster brake lights,power windows,locks though the car will start and run. my question is did I blow a main relay or something?

thanks

 

You blew the big alternator fuse at least. The spark you saw was caused by the big current going through the rectifying diodes via the alternator fuse.

 

you asked a question that only you can really answer, just check it out and post the answer for the rest of us so we can be careful not to cross them..... I always thought the post on the battery were different sizes...shows what I know now...

 

I see you posted on this link: https://www.clublexus.com/forums/ls4...nt-work-2.html
have you replaced your green relay??? why not?? try it and give us an answer.. thanks .. even if you only go to a salvage yard and get one, you have to assume a wrecked car was starting and running when wrecked..

 

billydpowe

could I take out the green fuse and jump the connections? I have read some earlier posts that said replacing the green fuse did not change anything

 

Yamae,
yes you are correct after close inspection during the day the element was burnt,it was the alt fuse 120 amp that is white in color my local dealership has it for $22.00 (part# 90982-08254). Is there a trick to getting the fuse out ? because it does not want to budge.

 

never mind I found it deeper in my search listing

https://www.clublexus.com/forums/ls4...use-blown.html

 

Just go to autozone/pepboys/advanced auto etc.... that fuse is like $4.

 

So I replaced the ALT fuse and I got back most of my lost functions except for a non-functioning power door lock,dome lights,power wheel tilt, alarm,dash clock, dash trunk release and key chime. the dash "air bag" light is activated and the headlights will only come on with engine running. another odd thing is that my voltage at the cig lighter reads 9.6 volts. but reads 12.4 volts at the battery. at the start of this thread I forgot to mention that when the car did not start I then plugged in my cig lighter voltage gauge which read 9.6 volts. so the question: Is the single-click starter and the 9.6 voltage cig lighter part of a starter relay? or starter solenoid issue??
thanks in advance for any suggestions.

 

Check other fuses under the hood and under the dash not only by your eyes but also by a multimeter.

As I wrote "at least" at my previous post, other than the ALT fuse, some more smaller fuses might be blown depending on how much and how long the reversed current was going through. It is not often the case but sometimes some units might be damaged by that and you need to replace those or fix opening the inside. But it is not easy for us to fix those without the skill and the detailed information. Those failed units had the negative voltage with the extremely low impedance and some semiconductors are killed.

As I fixed some of those units requested by local shop owners, the protection diode is mostly damaged or the internal fuse resistor is open. Sometimes other semiconductors are killed but those are not the often case.

 

Make sure the battery terminals and the clamps are clean. Also the junction where the cable is crimped to the clamp can get corrosion and cause a resistance. Check the voltage a the other end of the power wire. Also make sure ground is in good shape too. You could also have some relay or fuse terminals with corrosion.

 

Is the single-click starter and the 9.6 voltage cig lighter part of a starter relay? or starter solenoid issue??
thanks in advance for any suggestions.

sounds like solenoid to me...

 

I have checked all the under-dash fuses twice, I will have to check each item individually and I will update the post when I find out. wish me luck!

 

Just wanted to update the outcome of this problem: Earlier in the post I had replaced a blown radio fuse with a fuse (Neiko) that came from a fuse assortment pack from another used car purchase. These fuses (neiko) are junk, one of the blades of these fuses had broken-off into the fuse block so I could not tell that the connection was broken. I replaced the fuse with a better type and all of my electrical problems were solved.

 

Thanks for the update. So you had 2 blown fuses for the alternator and the radio. And you had a problem with a Neiko fuse. I don't know the brand Neiko at all and I searched the Net. They mainly sell tools putting the name USA on those but the actual productions are not done in USA.
Recently I find many tools and parts made in Asian countries near Japan, but as far as I know, they are just cheap and nothing more except some branded ones.