rljones

I spent some time looking over the wiring for the IS, trying to find an easy install for the illuminated scuff plates (ISP). I found one that works. I can post photos (I took some this time!) in a day or two.

skip this dotted section if you don't want electronic-type details:
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Basically, the standard plug is almost OK. There are two wires on the ISP: blue and gray. The blue gets the constant (+) power source from the plug that everyone has tried to connect. The gray, however, is not a simple ground. As I believe one or two others has suggested, an ECU ground is missing to enable the ISP to work.

Aside: should the wire colors be different---I don't see why Lexus would change production---you can verify the blue wire is the one NOT to cut and splice by measuring that it is the one that is getting the (+) voltage from the standard connector by measuring which of the two metal tabs in the connector on the harness side has the (+) voltage.

I figured that if the red light on the door comes on when the door is opened, why not used the switch that controls that red light? It turns out there is only one red wire connected to that switch. When the switch is released by opening the door, the voltage on this wire goes from 12-14V to 0V. Closing the door restores the voltage. So, to turn the lights off, Lexus seems to float the ground back up to the positive rail voltage. To turn on the lights, it creates a complete circuit by lowering the ground side to voltage ground.
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Parts needed (per side):
one red 18-22G wire taper (Radioshack / Kragen Auto / Home Depot). 22G or so sized wire (jumper wire) to run from the red wire behind the front door switch down to the front ISP. I used a little extra and wrapped it around one of the wire harnesses. You'll also need a soldering iron, or, a straight wire connector and crimper to splice the jumper wire into the gray wire on the ISP.

Instructions:
To start: take off the black plastic panel covering the seat belt area between the front and rear doors. Locate the single red wire that branches off a harness and goes to the rear of the door switch. Place the red wire taper on the red wire (there is an exposed section making ths step easy) and insert your jumper wire into the same taper. Keeping the wires positioned, press the metal tap securing the two wires. If you want to verify a proper connection at this stage, measure the voltage at the end your jumper wire or at the metal tap before you close the plastic insulation tab over it. The voltage will be >=12V with the front door closed and 0V with the door open. Dress (wrap around an existing harness, tape or tie) your jumper wire down its length to the ISP.

Next, cut back the black protective sleeve from the wires going into the connector on the ISP (making sure you don't cut any wires). Cut the gray wire flush on the connector to give you as much gray wire to work with as possible. (Do NOT cut the blue wire, as you will still plug the connector into its normal location for the positive voltage.)

Here is where you can differ from my install. I tinned both the gray wire and my jumper wire, placed a heat shrink tube on the jumper, soldered the ends together, and covered the joint with the heat shrink tubing. Another option is to used a single crimp connector to join the gray and jumper wires. You could also use another wire taper, but I think this is a less clean install.

Next, plug in the ISP and it shound come on when the door is opened and turn off when it is closed (or the switch is manually pressed). Replace the black cover over the seat belt area and press in the ISP and you're done. It took me about 10 min per side (once I'd figured out what to do).

Regards, Robert

eddiec

Excellent

rljones

Here are some photos. 1st: the red wire with taper installed. The brown wire is the jumper wire running to the ISP. 2nd: ISP with brown wire already soldered to gray wire; blue wire still intact for +V via standard connector. 3rd: door switch manually pushed off,leading to 4th image with ISP off. 5th: ISP turns on along with red door light when the switch is released and the door is open.

rljones

red jumper detail

rljones

ISP detail

tim817

Thanks a lot for the instructions and pics.

Payam

Great post, now that we know how it's done, I'll have to order it.

stangd1909

Can you make the first set of pics bigger......Looks pretty cool!




Great post!

rljones

stangd1909,

I did enlarge the 2 essential images and post them above. The other 3 images are just showing the LEXUS part on and off with the other image simply showing my finger pushing on the door switch.

The image showing the ISP connector detail is beneath the ISP. Again, the blue wire is left intact and my brown jumper wire is soldered (and covered by shrink tubing) to the gray wire. The connector is shown plugged into the harness. This connector is the only one beneath the scuff plate, so you cannot make a mistake and plug it into a wrong connector.

Regards, Robert

ecr527

Good post RL!! I'm sure a lot more people will be buying the scuff plates now.

stangd1909

Thanks!

Foxberry

I know I will be. Thanks RL!

Carson-Lex

Hey guys, Robert just PMed me about this thread, and man did he do some nice work. I just wanted to let everyone know that we never stopped selling the plates. They are still 109.00 each for the front, and 64.00 each for the rear. The rear are non lit, and inteded for those IS' that did not come with aluminum inserts in the rear sills. We do not list them on our site, but you can call me up and we can get an order out for you guys.

Thanks Rob for the heads up man.

chilexguy

my car is a IS 350 2006 nav without illuminated door panels.. is this fix for lighted door scuff plates for cars with stock existing?

or do you need luxury package wiring? i think luxury and sport models have illuminated doors right?

teejnut

iTrader: (6)

Are you guys expecting group buy for the sills anytime soon?