BullElk
SILVER Star
Did you get a new fuse box exactly like the one you replaced? Are you going to have the same issue with new box?
My immobilizer fix (1 Viewer)
- Thread starter medtro
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- Thread starter
- #262
I asked for pictures before and you said you have no pictures, but you have pictures now
.The information presented in the first post is to bypass internal fuse box problem between EFI fuse and relay. Your problem is after the relay or downstream of the relay like you said. These are 2 different problems. You are mixing the 2 problems here. To come in here to say it is not a permanent fix is misleading. First, you shouldn't have used it to fix your downstream problem to start with. It doesn't address any of your downstream problem. Second, this bypass scheme can't prevent the rest of the fuse box from going south.
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You clearly don’t understand the issue with the fuse box as a whole. The short and failure of the fuse box is the connection bar that is AFTER the fuse and relay. That is the issue. The short causes an over amperage draw on the original fuse location - blows the fuse, change the fuse - it starts for a while, upgrade the fuse - it starts for a while - eventually it will fail. Then put the jumper in - fine. Larger wires, they absorb the heat, amperage draw, etc and dissipate the heat, but eventually at some point - they will all fail. Look at the ROOT cause of the problem with the crank/no start - low voltage to the ECU. Why? If you have good voltage and continuity pre-fuse and post-relay - then it is in the box and that is the reason the ONLY permanent repair is to replace the fuse box.
Watch this video and it will help explain it - he pulled the fuse box apart. The same thing will happen to every fuse location you use.
As I understand it - Toyota upgrade the output side of the fuse boxes in ‘02 so this issue us generally only a problem in the early 100 series.
PS - You may have made a business out of selling the jumpers and while it may work for many people - it is not a permanent fix.
Watch this video and it will help explain it - he pulled the fuse box apart. The same thing will happen to every fuse location you use.
As I understand it - Toyota upgrade the output side of the fuse boxes in ‘02 so this issue us generally only a problem in the early 100 series.
PS - You may have made a business out of selling the jumpers and while it may work for many people - it is not a permanent fix.
Toyota upgraded the fuse box in ‘02 or ‘03 and this eliminated the issue. I purchased a NEW OEM with the newest part number avaialble so I assume it is the upgraded fuse box. No temp increases on the fuses or EFI relay. If you have a temp gun you can take the temp of the fuses and relay. For me - they both got hot, as well as the wires. I dealt with the issue for about 4 years. Upsized the fuse - temp fix. Replaced the EFI relay - temp fix. I built multiple jumpers - off of the open fuses and direct to the battery. They all worked, but if I drove for a couple hours - they all increased in temperature. I upgraded the wires on the upstream side of the relay and the downstream got hot (the relay).
I just picked up a ‘99 with 160k and I plan on doing the fuse box to ensure it is reliable. - if/when the crank/no start issue develops.
BullElk
SILVER Star
There are a few things with hundys that is sure to happen at some time or another. Not many things but a few and this faulty fuse issue is one of them for a few model years. And when that has happened to many hundy owners here......the kit, the knowledge and assistance @medtro has provided over the years is significant and appreciated. And so far I would say it is a permanent fix for a fraction of cost and time.
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FWIW, Joey aka @NLXTACY recently swapped in a new fuse box recently too on his 100. @LWA55DAL any idea what causes the short that initiates the waterfall of problems with the EFI fuse/relay? Thankfully the fuse receptacle on my '99 only slightly burned/melted and didn't end up in a bonfire.
What is to prevent the problem from returning sometime after swapping in a new fuse box? Many years ago, I remember reading it was a design flaw which Toyota corrected in '02 or '03 by splitting the load from one fuse into two fuses?
The same problem arose on my '99 when I was truly in the middle of nowhere Nevada on an elk hunting trip. Fortunately we were traveling in pairs and I was able to hop a ride with my buddy and drive to just enough cell service to get a band-aid fix ala this thread to at least make it drivable until I could get @medtro kit. So far, some 10-years later @medtro fix is still working for me albeit its not a DD for me.
This and the charcoal canister are two design flaws that have, at least relative to the CC, the potential to burn a 100 to the ground...something Toyota & our guberment (IMHO) should have recalled years ago...2 cents on my part.
What is to prevent the problem from returning sometime after swapping in a new fuse box? Many years ago, I remember reading it was a design flaw which Toyota corrected in '02 or '03 by splitting the load from one fuse into two fuses?
The same problem arose on my '99 when I was truly in the middle of nowhere Nevada on an elk hunting trip. Fortunately we were traveling in pairs and I was able to hop a ride with my buddy and drive to just enough cell service to get a band-aid fix ala this thread to at least make it drivable until I could get @medtro kit. So far, some 10-years later @medtro fix is still working for me albeit its not a DD for me.
This and the charcoal canister are two design flaws that have, at least relative to the CC, the potential to burn a 100 to the ground...something Toyota & our guberment (IMHO) should have recalled years ago...2 cents on my part.
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- Thread starter
- #267
Thanks for clarifying the issue, and your word "jumper" is very confusing. As far as I know you are the only one had this problem. I am glad you resolved the issue with a new fuse box.
I watched the video and he showed the problem at the fuse location, which is what I expected. My kit bypasses the exact same problem that he showed. I didn't see him showing any problem after the relay to support your claim.
This is the first time I read about Toyota upgraded the output side of the fuse box in 2002. Based on the information from people who purchased the kit, 2002 LC/LX is not immune to the problem described in the first post. If what you said is true, then upgraded output side of the fuse box didn't address the problem before the relay. Someone with 2002 LC just PM'd me today saying his mechanic told him he needs a new fuse box. May be a new fuse box that is improved in 2002 is not a permanent fix after all???
Time will tell if this is a permanent fix or not.
If you read carefully, I actually showed people how to build the kit in this thread. I don't promote my kit in tech forum. Thanks for the free plug.
- Thread starter
- #268
Are you referring to the new fuse box design used in the 2003+ models? Toyota upgraded the EFI circuit from 20A to 25A in the new fuse box design. It is a whole different fuse box that can't be used for earlier models.
Thanks for the support and confidence. It has been 5 years only for you
Seems like 10 
By popular request here are the pictures from my old fuse box and the wires. I used one of the open fuse locations to power the relay and as you can see the post relay side is what got hot. Again - this was only on longer drives but in Texas it’s pretty typical to drive 3 hours and that’s when it was noticeable.
If I recall correctly there is a supperceding part # on the fuse box and that’s the upgraded one that eliminates the issue. The install wasn’t exactly simple, but can be done with a basic knowledge and some patience. The biggest challenge is getting the right amount of room to unplug the existing wires. You need to remove the charcoal canister.
If I recall correctly there is a supperceding part # on the fuse box and that’s the upgraded one that eliminates the issue. The install wasn’t exactly simple, but can be done with a basic knowledge and some patience. The biggest challenge is getting the right amount of room to unplug the existing wires. You need to remove the charcoal canister.
- Thread starter
- #271
The burn mark is worse on the relay side. If the black mark on the wire means anything, then my guess is your relay generated the heat and sent it down to the fuse box. I don't see any evidence of fuse box (or what you called as after relay) generated the heat and sent it back up to the relay in these pictures.
The relay that I use in the kit that I am selling is rated for 40A, perhaps it generates less heat and has better thermal characteristic than your 20A OEM relay. I haven't seen problem like this from my kit.
- Thread starter
- #272
This 2002 LC owner was instructed by his mechanic to order the kit. I will be sending it to the shop tomorrow.
Maybe the relay but I did install the newest relay from the dealer when I built the kit. As mentioned - I built quite a few of them and also alternated relays - same heat issue. Just problem solving but maybe it was the relay. The new fuse box came with a number of relays but NOT the EFI relay so I used the same one and zero heat or issues so I would rule out the relay.
- Thread starter
- #274
You talked about downstream, post relay, downstream of the relay power ..... numerous times but I don't see anything from you that supports those claims.
- Thread starter
- #275
After seeing your pictures, I am sure you didn't have good voltage post relay. That is WHY you had low voltage to ECU and crank with no start. My experince on this is a small voltage drop is enough to cause it not to start.
I've been running the same thin wire with burn marks for 6 years now with no issues and is my DD. If it ever fails I will report back.
- Thread starter
- #277
It is very clear that your heat source is from the relay, not from downstream. If the relay is good then I would look into connection and wire size.
I agree on the hotter part but not on the most AMPS part. Amperage/current remains constant in that path, resistance increases when there is bad connection or corrosion, more heat is generated with higher resistance from the same amount of current. Voltage drop increases with higher resistance too. Furthermore, higher temperature (from the heat) reduces the conductivity of the conductor, that means higher resistance from higher temperature. It goes downhill from there, higher resistance causes more heat
more heat causes higher resistance 
higher resistance causes higher voltage drop.
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For the record - none of the kits I built every resulted in crank/no start but using various wire sizes and new and old relays they both got hot. Crimp connectors, heat crimp, etc. I didn’t solder the connections as I got good crimps and made sure of that. The only reason I replaced the fuse box was due to the wire melting and heat issues. Would it run today? Probably, but this is a daily forever in rotation with the other LC’s so for $500 shipped to my door - I replaced the fuse box.
I will crack open the fuse box eventually and post pictures. I agree with the amperage/voltage commments above - my point is - I am VERY sure the resistance that is resulting in higher heat, amperage increase, voltage drop, at least in my case, is in the fuse box.
Direct to battery - no relay - and it gets hot.
We can debate wire size, but I used 14 and 12 and either one should easily handle 20 or 30 amps of 12v given the distance. In theory - it’s a voltage regulator only - at least to the ECU.
If the issue is in the fuse box - the larger wire is only going to mask an underlying issue in the box.
I will crack open the fuse box eventually and post pictures. I agree with the amperage/voltage commments above - my point is - I am VERY sure the resistance that is resulting in higher heat, amperage increase, voltage drop, at least in my case, is in the fuse box.
Direct to battery - no relay - and it gets hot.
We can debate wire size, but I used 14 and 12 and either one should easily handle 20 or 30 amps of 12v given the distance. In theory - it’s a voltage regulator only - at least to the ECU.
If the issue is in the fuse box - the larger wire is only going to mask an underlying issue in the box.
If I may add, 82720-60023
The 98-02 box is about $380 + shipping on partsouq. Close to $500 + tax shipped when Toyota/Lexus is running a discount.
You get the box + all new fuses and relays with the exception of 3 pieces you need a swappa from the old box if I recall this correctly.
The 98-02 box is about $380 + shipping on partsouq. Close to $500 + tax shipped when Toyota/Lexus is running a discount.
You get the box + all new fuses and relays with the exception of 3 pieces you need a swappa from the old box if I recall this correctly.
