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Lexus GS450h Transmission Inverter High Voltage Cable Repair
Posted: Tue Jul 11, 2023 5:51 am
by Gregski
you may find this thread useful if your seller removed the transmission by using nothing but a machete, like mine did
please take the time to examine your fat orange high voltage cables prior to installing them, here's what mine looked like when they arrived, I put off the repair as long as I could
difficult to see in the pic but I could see some exposed copper wire in one of the three leads in there
Re: Lexus GS450h Transmission Inverter High Voltage Cable Repair
Posted: Tue Jul 11, 2023 5:58 am
by Gregski
this is tedious work and is probably best performed on the comfort of a work bench or garage floor prior to mounting the gear box in the vehicle
I like to take my time and peel the tape it's not that bad, twist the cable slowly and you will see the starts or ends of the tape, I only use a razor blade when i absolutely can't find the end of the tape to start pealing, this makes the process go slower but it forces you to examine every inch of the cable
after removing the orange loom / conduit whatever you like to call it, we can see more of the damage to the shielding/reinforcement wire? please tell me what that stuff is
so then I slid the rubber boot back
and went after more tape, this time to loosen up that silver webbing
the webbing does slide back if you are careful because it gets caught on these two white zip ties
Re: Lexus GS450h Transmission Inverter High Voltage Cable Repair
Posted: Tue Jul 11, 2023 6:03 am
by Gregski
and now I could see the extent of the damage
Re: Lexus GS450h Transmission Inverter High Voltage Cable Repair
Posted: Tue Jul 11, 2023 6:05 am
by Gregski
I could have just wrapped some electrical tape, but my roll of orange Tesa tape hasn't arrived yet, plus we have standards over at Good Enuff Garage, so I decided to do the right thing, and see if I can dismantle this 3 amigos plug, I used a red sharpie to mark the patient and it's orientation in the plug, cause my memory is so bad I can hide my own Easter eggs
Re: Lexus GS450h Transmission Inverter High Voltage Cable Repair
Posted: Tue Jul 11, 2023 6:09 am
by Gregski
I was very pleased to see that a reasonable sized heat shrinker would just barely slide over the blade terminal
and since it was late at night and our daughters room is right above the work shop, I decided to use the caveman torch instead of my Dewalt heat gun, (I am pretty sure 9 times out of 10 that's what I use, lol)
Re: Lexus GS450h Transmission Inverter High Voltage Cable Repair
Posted: Tue Jul 11, 2023 6:11 am
by Gregski
earlier on I should have mentioned that I slid the big fat red O-ring or grommet way back past the damaged area, cause no way was the heat shrink gonna make it over that and maybe I could have slid it off the cable over the blade terminal I don't know
so here it is trying to find it's way back home
Re: Lexus GS450h Transmission Inverter High Voltage Cable Repair
Posted: Tue Jul 11, 2023 6:13 am
by Gregski
I must say I am pleased and impressed that Mr. Toyota made this part serviceable, he will be getting a Christmas card this year
Hard to see in this pic but
this black plug has 4 clips on it (two per side) that are mostly broken because the metal piece that goes over it must have been removed by a gorilla
Re: Lexus GS450h Transmission Inverter High Voltage Cable Repair
Posted: Tue Jul 11, 2023 6:16 am
by Gregski
I am very pleased with this repair, and learned we could swap the cables around on both ends (Inverter and Transmission to make the cables hug the Inverter from both sides instead of both from the same side (just a thought, for aesthetics mostly, but maybe for reachability too)
Re: Lexus GS450h Transmission Inverter High Voltage Cable Repair
Posted: Tue Jul 11, 2023 6:19 am
by Gregski
I wasn't even done patting myself on the back when I decided to check the other side, I vaguely recalled different cable scars than what I showed in the first post, could that come from the other cable? ah yup !
- this-is-my-surprised-face.jpg (53.58 KiB) Viewed 3034 times
Re: Lexus GS450h Transmission Inverter High Voltage Cable Repair
Posted: Wed Jul 12, 2023 7:39 pm
by Gregski
a couple point of interest as I took on the second cable
though there are three tabs holding this guys teeth in, you don't need three hands to do undo them simultaneously, simple undo them one by one, gently pry the tab away from the blade and press the blade in about 1/4 inch
it works even better if you don't have a broken screwdriver
Note To Self: hug a random Lexus engineer
Re: Lexus GS450h Transmission Inverter High Voltage Cable Repair
Posted: Wed Jul 12, 2023 9:27 pm
by RetroZero
Don't know how/if you will be controlling HV isolation, but the little I know is there is 250amps going through those orange cables. They have an isolation value to respect in order to not have current passing to chassis ground (low voltage system). At the least I would say your heat shrink needs to be the same thickness /insulation value. Keep that repair area far away from any conductive materials too. We have problems where ferrets bite into the cables and just one pin size hole in the inner orange cabling sets a HV error and the vehicle is immobilised - overkill? For you to judge, but looking at the awesome build you're doing, you won't want to risk anything... In new EV's /hybrids, the outer metal casing is used to monitor the potential difference between HV and chassis ground. Otherwise, great to see toyota thought about serviceable components.
Re: Lexus GS450h Transmission Inverter High Voltage Cable Repair
Posted: Fri Jul 14, 2023 1:40 pm
by Gregski
RetroZero wrote: ↑Wed Jul 12, 2023 9:27 pm
Don't know how/if you will be controlling HV isolation, but the little I know is there is 250amps going through those orange cables. They have an isolation value to respect in order to not have current passing to chassis ground (low voltage system). At the least I would say your heat shrink needs to be the same thickness /insulation value. Keep that repair area far away from any conductive materials too. We have problems where ferrets bite into the cables and just one pin size hole in the inner orange cabling sets a HV error and the vehicle is immobilised - overkill? For you to judge, but looking at the awesome build you're doing, you won't want to risk anything... In new EV's /hybrids, the outer metal casing is used to monitor the potential difference between HV and chassis ground. Otherwise, great to see toyota thought about serviceable components.
thank you, I appreciate the input, and I am keeping an eye open for cables on eBay and locally, as I attempt to talk at least one of our kids from going to college, LoL
Part Numbers
Re: Lexus GS450h Transmission Inverter High Voltage Cable Repair
Posted: Mon Jul 17, 2023 10:09 pm
by xp677
The outer braid is needed on any VFD-driven motor cables to reduce EMI. There should be an uninterrupted faraday cage from beginning to end, the inverter and transmission casing, along with this braid, fulfil that.
See here:
https://library.e.abb.com/public/a8dc0a ... N_RevD.pdf
Page 24 onwards is relevant for this application.