jpw

I have a 92 SC400

I've had sporadic electrical issues for a few years. In the past, I just got a new battery and installed a new alternator and I guess if fixed it temporarily.

Lately I've noticed that turn signals dim the dash lights. A few days ago my wife was driving and she said the entire electrical system just shut down while she was in our neighborhood - total electrical failure.

She stopped, and restarted everything was fine.

All the while, I've been checking the charge from the new (1 year old) alternator and it's spec, about 14.5 volts while idling.

Then went to our anniversary dinner. I wanted to take the Tacoma, she wanted to take the Lex - of course we take the lex.

When we left dinner, everything was dim - very dim. It showed symptoms of a very low battery, but unfortunately when we returned to pull the battery out, I didn't check the voltage. The battery is only about 2 years old and it's one of the top end Diehards.

I'm wondering if it's the ground from the battery...

Can a crappy ground produce symptoms that are similar to a dead battery ?

Does the battery ground connect to the engine right near the oil filter?

I tried to get under there and see and that's what it appears to be. I disconnected it and tried to clean it, but could only do about 10% of a cleaning that I wanted to do since the oil filter was right there - it looked a bit corroded. I'm changing the oil so I can take the filter off and clean it thoroughly.

I've also read about people installing what they call "grounding kits' , or "my own Ground setup".

Is that simply making a good connection from the negative battery terminal to some good ground on the engine ?

Do you just disconnect the ground wire from the battery and connect your own wire from the neg battery terminal to the ground ?

Thanks for the help! I rarely take my car into the shop but it's getting close to being there - I really detest electrical problems....

jpw

Ok, I asked my neighbor and he recommended just getting a battery cable and find a place on the frame to connect it to the neg terminal. I got a 4 gauge wire and am installing it now... Have to dremel some of the paint away first so it gets a good connection..

2GSKaizen

iTrader: (1)

That should help. I would also run a new wire from the battery - to a clean spot on the engine block also.

scENFORCER

I went through this same issue with my old SC, but it seemed to go away when I installed a new alternator, battery, and did the 'big 3 upgrade'. Seems like SC's start expieriencing ground issues when they get older..

Here's a recent link to a member who was having the same issues. Might give you some insight..
https://www.clublexus.com/forums/per...aise-idle.html

SC400slide

iTrader: (11)

I might do the big 3 upgrade...probably a good idea for most SC's that are 20+ years old.

jpw

Thanks everyone - I didn't see much of a difference in terms of the dash lights dimming while the turn signals are on. I used a 4gauge wire.
I really appreciate the link to the big 3 and will report back here on the results after I get in installed..

jpw

To the folks who have done this before, do you have any good spots you can suggest for attaching a ground wire to the engine block?

Thanks

TheAzn

iTrader: (2)

Buy a grounding kit or you can make your own. A grounding kit is basically 4 gauge wires of various lengths with round loop ends crimped on each end. You can buy these ends from any auto part store in the section where battery terminals and stuff are. The wires you can get from an automotive audio place.

Basically, install the wires tracing the existing factory grounding wires.

Battery to Chassis
Chassis to Intake Manifold
Chassis to Engine Block
Battery to Alternator (the mounting bolt, NOT the terminal on the alternator)

I forgot the few others. But the more important one is the battery-to-chassis and chassis-to-engine.

I had your issue before. The car would start fine. At random time, the entire electrical power would either trickle or completely go ou.

jpw

Thanks Theazn. I'm already gathering the parts. I'm using the big 3 as a guide . http://www.the12volt.com/installbay/...TID~73496~PN~1

I really appreciate your help but was wondering if you could answer :

-This site suggests using 1 gauge wire but you used 4 - did you consider using 1 ? I guess if it worked for you there's no reason it won't for me - I'd much rather use 4g since it's cheaper and easier to work with than 1

-Your last one was Battery to alternator. Are you talking negative batt terminal to alternator mounting bolt ?

The big 3 suggest Batt+ to Alternator+ - I'm assuming you didn't do that ? I guess since I have a grounding issue there wouldn't be a reason to go from Batt+ to Alt+

thanks!
I now have batt - to the frame (next to the pillar). It didn't help my blinking-dimming-the-dash-lights issue so I plan to do more grounding connections..

jpw

OK, so I did the following connections using 4 Gauge wire:

1. Neg battery to Frame (by the pillar)
2. Intake Plenum area (engine) to the Frame (by the Pillar)..

So far we've been driving it for about 6 weeks nearly every day and there have been no starting or stalling problems, which is great.

Also, I did find the 'factory' engine to frame ground strap. I was under the car with my feet to the front, right under towards the left side of the car, probably right under the driver's seat. The right side of the wire connected to one of the left side transmission mounting bolts located just to the right side of the left Catalytic Converter. The left side was just connected to the frame on the left side of that same CAT...
I cleaned both of those connections really well, which couldn't hurt, but maybe help.

Frame connection:




Tranny Connection:

jpw

FYI if anyone's looking at this, I took these pics while laying down w/my feet towards the front of the car so the bottom of each pic is the front of the car.

t2d2

iTrader: (8)

I recently fixed a grounding issue on my other car and it made a world of difference. When it goes, it goes bad.

This thread got me to thinking, when the SC gauge needles start flickering, has anyone tried them in another car to see if it's a ground/voltage issue as much as the needles themselves? I know, it's a long shot, but my stereo's dimmer signal gets confused by things like putting it into park and the needles sort of follow along, so I'm thinking there's a connection to what is normally attributed to alternator weakness but might be ground related...

TheAzn

iTrader: (2)

Is it just the needles flickering? If it is, it's the needle themselves. They're all a line of tiny LEDs that has seen better days. Mines flicker during the daytime, when my headlights are on they are stable. My fuel needle don't light at all.

The needles are year specific I think. I think 92-94, 95-96 and 97+.

Oh, I didnt think of using anything bigger that 4g wire. I'm sure smaller wires would've still worked, 12g, etc. 4g is plenty, most aftermarket audio amps suggest that. It's grounding anything like that so it's beyond more than good, reliability added.

t2d2

iTrader: (8)

I haven't noticed any other lights flickering or dimming, but I've been told that stereo flickering is often a sign of a weak alternator, and the symptoms sort of track each other, so I was free wheeling a bit and wondering if there's a possible connection between two common elements as the SCs age: flickering needles and bad ground.

jpw

Before I did the above, I replaced my dash lights w/LED's and they still slightly (very slightly) dim when I first put on the turn signal.

But after doing the above I don't get battery drain nor total electrical failure.

I can live with the slightly dimming lights - no biggie.