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As reported earlier in this posting, the main negative battery cable grounds to the inner fender well via a flag terminal before terminating at the Air Conditioner Compressor.
This post focuses on the compessor terminus
The air conditioner compressor housing is comprised of Aluminum, so grounding a copper cable with copper lug mating to that surface would react-oxidize-corrode, etc, in short order.... It would appear Toyota determined to use an L-shaped "Compressor Stay" between the ground cable and compressor to avoid dissimilar metal corrosion .
This plate and fastener assembly corrode over time resulting in increased resistance and voltage drop...
As this terminus is near the bottom of the engine, those running without the bottom engine cover are more susceptible to accelerated ground degradation...especially if you run in salted roads. Main negative battery cable terminates at the AC Compressor and Oil filter housing bracket.. Lexus incorporated a plated metal compressor stay. The original on this 99 LS400 is tired. This original compressor stay is from a well maintained 1999 LS400...both plate and hardware have experienced better days. Older LS400's surveyed are far worse... The replacement compressor stay has a different finish than the original dichromate finish(? Used a test meter and this black finish proved conductive. The bolt and nut are steel, generously Zinc-plated. The L-shaped Compressor Stay grounds to the engine block at oil filter bracket housing via the hexagon-shaped spacer shown. Plenty of corrosion depicted here. Not replaced, but will be upon next parts order. Compressor Stay is 88431and nut is 90179-08037 in Lexus exploded parts diagram. The negative ground strap mounting bolt is not depicted...and was unable to locate a specific part number in the Lexus system.....perhaps a member can advise. (The bolt I used was the engine-to- frame ground strap bolt...the clamping washer is smaller however it is not an inferior thread-cutting/forming style bolt) Anyone with a P.N.? The Compressor Stay ground plate straddles oil filter bracket hex standoff bolt # 90116-08319..The original is corroded which would respond well to replacement.
Some before and after images of replacement threaded hex bolt standoff that holds the oil filter bracket extension to the engine and fastens the "compressor stay" plate which is terminus of battery main negative grounding cable.
The original threaded hex bolt standoff is corroded....resistance/voltage drop to block....Could it me cleaned..possibly, but the protective coating is toast and well worth replacing for a few dollars Image depicts the threaded hex standoff in relation to compressor stay. The thread forming screw at bottom affiixing negative battery cable was also replaced. New corrosion free stud from Lexus...about $1.50.
Toss those corroded parts in a cup of vinegar for a few days you will be very surprised how they look. They will need all grease cleaned off before the dipping process.
In addition to the main negative battery cable (battery - fender well-AC compressor) and the secondary ground cable (Right engine block motor mount bracket - chassis) there also appears to be a third ground cable from the left side of lower engine block that disappers into the engine harness bundle...
Anyone know where this terminates?
Working on engineering drawings for the other two cables....and would like to include the third cable in the mix .not sure if same or different from the other 16" ground....
In addition to the main negative battery cable (battery - fender well-AC compressor) and the secondary ground cable (Right engine block motor mount bracket - chassis) there also appears to be a third ground cable from the left side of lower engine block that disappers into the engine harness bundle...
Anyone know where this terminates?
Working on engineering drawings for the other two cables....and would like to include the third cable in the mix .not sure if same or different from the other
16" ground....
On 1999 LS400, removal of the air cleaner assembly exposes two grounding wires affixed to the passenger side fender/chassis.
Removed the bolt to assess its condition...not bad, but minor corrossion of plated fastener.
Cleaned terminal and will replace bolt with an OEM fastener Two wires from the harness assembly ground with single bolt at chassis. This imagec aken with air cleaner assembly removed. Close up of ground point. Slightly crusty after 18 years...will clean the terminal.and replace the bolt (although will inquire if raw terminal lug is avaiilable) Condition of fastener...
For 1995-2000 LS400 (It might fit 1990-1992 and 1993-1994..someone review drawings and chime in here if they have first-hand knowledge)
QuickCable has produced draft engineering drawings for the main negative battery cable (runs from battery to inner fender well and terminates at AC compressor) and the secondary ground cable(runs from passenger side motor mount to chassis)
Original cables are 6 gage copper course stranded wire and replacement cables are 4 gage fine strand tin-plated marine grade copper wire..so an improvement...the 6 gage wiring is a choke point with all accessories running..not to mention high power aftermarket sound systems...
The tin-plated copper lugs on the secondary cable are heavier with tighter tolerance stud holes in relation to the mounting hardware.
...HOWEVER....the main negative battery clamp is NOT what was specified...and have requested it be changed to the more robust tin plated cast copper clamp depicted earlier in this post
Lexus welded/soldered the negative battery clamp at the cable interface due to corrosion (some earlier Lexus models had a replaceable negative battery clamp)
I am also presenting additional hardware and plastic clamp P.N.'s to acquire from Lexus
Main negative battery cable...have requested QuickCable modify the drawing to the battery clamp specified... Secondary negative ground cable to specification. Be sure to replace original mounting hardware with OEM fasteners.
Lexus PN 90080-11396. Use for secondary negative ground cable.. The chassis side bolt is now using a correct non-thread forming bolt. The engine mount ground point is correct. Originals were cleaned at one point but time to replace Secondary cable at chassis...this is replacement battery cable with original bolt. ....and with new bolt...quality of replacement is superb...quality plating almost looks like stainless steel, with an integral flat washer. The locking washer is combination wave/split washer....provides both tension and locking.. This original plastic clamp is tired...located midpoint on secondary negative ground wire. New plastic clamp New midpoint wire clamp installed Old clamp aside new This image depicts another engine block ground point on the drivers side..the ground disappears into a harness loom. Used same bolt as with secondary cable . This image is after bolt removed...it is in a tight area above steering rack..the original bolt was not bad but replaced it anyway.. Required a long socket extension and a swivel.to access..if your swivel has too much play then lightly wrap some scotch tape around it while guiding replacement bolt into place. .be sure not to cross thread..!!
I see no need to replace any of those fasteners just because they look bad. First wire brush them and then soak them in vinegar for a day or two and they will come out like new. Spray some metal etch on them if the coating is removed and use battery protector on them and the cable end.
I'd check the actual voltage drop first. As far as I check, I didn't find any bad ground points.
Toyota knows how important it is to minimize the problem of metal to metal contact and there seldom happens Galvanic corrosions.
I see no need to replace any of those fasteners just because they look bad. First wire brush them and then soak them in vinegar for a day or two and they will come out like new. Spray some metal etch on them if the coating is removed and use battery protector on them and the cable end.
The plating dimishes over time and "wire brushing".will only compromise it further.
The plating prevents galvanic reaction; corrosion.
Keep in mind you have an Aluminum block, a copper cable and (tin-plated) lug... and the fastener has to work between all of these dissimilar metals..
Toyota researched this thoroughly, which explains why I prefer OEM fasteners..
Zinc-plated steel bolts work well...as long as integrity of protective plating remains intact.
For those Lexus owners running without the lower engine cover or salt laden roads, then worth looking into.
Not going to wire brush the parts or use vinegar...less expensive to simply replace.
Whether voltage drop or not, and it is my belief reusing old faateners doesnot improve the situation, current carrying capacity is also a factor to consider.
Meanwhile, hope everyone enjoys the engineering drawings and the engineered solutiom presented.
If anyone mentions washing with vinegar again, I will have my girlfriend reply.....
Whenever I replace just about anny component, I advance purchase new connector shells, rubber bushings , o-rings, or fastenes to pair with it.
There are kits to reestablish a coating on bolts.
They also have them for other coatings as well. If a person is doing a lot of fastener replacements this can be a cheaper way to go. http://www.eastwood.com/ew-electropl...-tin-zinc.html
The plating dimishes over time and "wire brushing".will only compromise it further.
The plating prevents galvanic reaction; corrosion.
Keep in mind you have an Aluminum block, a copper cable and (tin-plated) lug... and the fastener has to work between all of these dissimilar metals..
Toyota researched this thoroughly, which explains why I prefer OEM fasteners..
Zinc-plated steel bolts work well...as long as integrity of protective plating remains intact.
For those Lexus owners running without the lower engine cover or salt laden roads, then worth looking into.
Not going to wire brush the parts or use vinegar...less expensive to simply replace.
Whether voltage drop or not, and it is my belief reusing old faateners doesnot improve the situation, current carrying capacity is also a factor to consider.
Meanwhile, hope everyone enjoys the engineering drawings and the engineered solutiom presented.
If anyone mentions washing with vinegar again, I will have my girlfriend reply.....
Whenever I replace just about anny component, I advance purchase new connector shells, rubber bushings , o-rings, or fastenes to pair with it.
Anyone replace their negative ground cables or are contemplating doing so?
Anyone replace their negative ground cables or are contemplating doing so?
I have never reefed on my battery terminals. Just a light press with a little twist, a slight bunt on the 10mm nuts, and if the cable end could not twist, that was tight enough. If everything is clean and treated with a corrosion/oxidation barrier, there is no need to distort the terminal ends.
My 1992 Lexus did 16 years in the northeast salted road environment. Every electrical connection I could reach was cleaned and coated with a liberal dose of De-Ox dielectric grease, battery terminals, light sockets, fuses and relays. Without oxygen, there was no corrosion for the next 8 years. I did, in a couple of instances, sand/scrape through the zinc plating. Nonetheless, the De-Ox kept the electrical conductivity optimal enough for a flawless electrical system.
Colin YMMV
I ended up doing the main negative, and the secondary on the passenger side, but I did it before you had the final all-in-one solution from Quik Cable available. I just rounded up all of the materials you mentioned on the first page and terminated everything myself. Thanks!
For 1995-2000 LS400 (It might fit 1990-1992 and 1993-1994..someone review drawings and chime in here if they have first-hand knowledge)
QuickCable has produced draft engineering drawings for the main negative battery cable (runs from battery to inner fender well and terminates at AC compressor) and the secondary ground cable(runs from passenger side motor mount to chassis)
Original cables are 6 gage copper course stranded wire and replacement cables are 4 gage fine strand tin-plated marine grade copper wire..so an improvement...the 6 gage wiring is a choke point with all accessories running..not to mention high power aftermarket sound systems...
The tin-plated copper lugs on the secondary cable are heavier with tighter tolerance stud holes in relation to the mounting hardware.
...HOWEVER....the main negative battery clamp is NOT what was specified...and have requested it be changed to the more robust tin plated cast copper clamp depicted earlier in this post
Lexus welded/soldered the negative battery clamp at the cable interface due to corrosion (some earlier Lexus models had a replaceable negative battery clamp)
I am also presenting additional hardware and plastic clamp P.N.'s to acquire from Lexus
Main negative battery cable...have requested QuickCable modify the drawing to the battery clamp specified... Secondary negative ground cable to specification. Be sure to replace original mounting hardware with OEM fasteners.
Lexus PN 90080-11396. Use for secondary negative ground cable.. The chassis side bolt is now using a correct non-thread forming bolt. The engine mount ground point is correct. Originals were cleaned at one point but time to replace Secondary cable at chassis...this is replacement battery cable with original bolt. ....and with new bolt...quality of replacement is superb...quality plating almost looks like stainless steel, with an integral flat washer. The locking washer is combination wave/split washer....provides both tension and locking.. This original plastic clamp is tired...located midpoint on secondary negative ground wire. New plastic clamp New midpoint wire clamp installed Old clamp aside new This image depicts another engine block ground point on the drivers side..the ground disappears into a harness loom. Used same bolt as with secondary cable . This image is after bolt removed...it is in a tight area above steering rack..the original bolt was not bad but replaced it anyway.. Required a long socket extension and a swivel.to access..if your swivel has too much play then lightly wrap some scotch tape around it while guiding replacement bolt into place. .be sure not to cross thread..!!
Attached is an image of improved 4 gauge battery cable (vs OEM 6 gauge) to ground (A.C. compressor stay) assembly.
Heavier 90 degree 5/16" stud hole tin-plated copper ground lug, crimped to 4 gauge marine cable with Tin-plated strands (fine)
Tin-plated center flag terminal with correct 1/4" stud hole to match the OEM ground screw.
Negative battery clamp is Tin-plated cast copper, with ground wire inserted into pre-soldered barrel which promotes increased current carrying capacity, eliminatrs corrosion creep and offers decreased resistance.
Should improve electrical/electronics system and engine/systems related performance over aged stock battery ground cable.
Finished negative battery post to ground cable assembly .....
01-29-17, 07:50 PM
