Retro fitting radar distance cruise control.

[Britprius]

Not wishing to continue hijacking member Collins (Crow1342) post  "Wheels, and workshop manuals GS450H" I am staring a thread on retro fitting radar distance control to the GS 350, and GS450H  2006/2011. It will almost certainly apply to other variants in the Lexus range. 


I have not as yet completed this but I am at a stage where I can pass on my findings so far. I must thank member Chris (Mihanicos) for his invaluable help with supplying circuit diagram information, that I could not find. A problem I have now resolved. So just to wet your appetite my progress so far. 

After studying the circuit diagrams for both versions of the cars "those fitted, and those not fitted" with radar cruise control known as "ACC automatic cruise control" I came to the following conclusions:-
As long as the required wiring was fitted the concept was feasible. 
The hardware that is missing amounts to four items:-
The distance control module ECU 88240-30410.
The millimeter radar cruise unit transmitter 88210-62010
The steering wheel switch that sets the distance. Part number not known at the moment.
A replacement Lexus logo badge for the front grill suitable for radar to pass through.

After checking in the dashboard above the accelerator pedal where the distance control module should be I found the wiring, and plug for this unit just taped to the loom to be in place along with mounting threaded pins. This plug was live in that there were 12 volt feeds, and grounds at the relevent pins.  All that is required to fasten the ECU is two 10mm spanner size nuts, and plug the unit in.

Following the circuit diagram I found the wiring goes through two plug, and sockets joining sections of the loom. The first plug, and socket designated (AL2) then the wires continue on to plug, and socket (BA2). These are gray components mounted in the main fuse/relay box under the bonnet positioned in the centre front of this box. On inspection of this plug with multiple wires going into it I found that there were no wires fitted on the outlet side "top" for connecting pins 1 to 5. These pins are marked 1 to 5 and are the connections required to extend the wiring loom to radar transmitter that sits in front of the radiators, and behind the Lexus front badge. This part of the wiring loom is not fitted.

I have bought of eBay both the ECU 88240-30410 for £20 delivered from Lithuania advertised at £45, and the radar unit 88210-62010 for £45 advertised at £120. Do not be afraid to low bids on items marked "Make an offer". Both my bids were accepted immediately I made them meaning I did not have to wait for the seller to accept the offer.

I have made up the section of wiring loom missing from the socket (BA2) to the radar unit using some old computer motherboard plugs removing the pin connectors for fitting to the (BA2) loom plug. As this only consists of five wires, and about three feet long it is not difficult to make up.
The other wiring that is missing along with a micro switch is in the steering wheel. The wiring into the steering wheel through the clock spring is there, but to select the set distance the wire must be grounded each time the operating switch is pressed.I may make up my own switch mechanism, and single wire if I cannot find a secondhand switch on line.

The control ECU has been fitted to the existing mounting points under the dash, and the existing wiring plugged in.

When the weather improves "it's been wet here the last three days" I will fit the DIY loom, and the radar transmitter. Then I will dismantle the steering wheel to fabricate the distance control switch mechanism. I have already noted that there is a knockout in the wheel where the switch should be mounted. I will also take some pictures so that the positions of the various components can be seen, and how they are connected.

Total cost so far is £65. This may rise a little if I can find a steering wheel control switch, but I am sure I can fabricate something if required or until I can obtain one. The expensive item looks like it will be the cheapest looking item. The front Lexus L badge that seems to be around £110. I may have to see what I can come up with printing wise to overcome this.

I am hoping that the existing ECU's have the software already installed, and that no further ECU replacement is required. I do not think this is the case as all the ECU's on the two versions have the same part numbers.

John.

[Shahpor]

Outstanding work as always John.

I'm sure you will succeed and it will be of great use to other forum members.

[Herbie]

Brilliant John, I'm already eagerly awaiting the next installment!

[ColinBarber]

56 minutes ago, Britprius said:

The steering wheel switch that sets the distance. Part number not known at the moment.

84250A SWITCH ASSY, STEERING PAD 84250-30400-C0	PRE-COLLISION SYSTEM-MILLI-WAVE RADAR TYPE, BLACK, TRIM04, 1*, 2*
84250-30400-E0	PRE-COLLISION SYSTEM-MILLI-WAVE RADAR TYPE, ORCHID BROWN, TRIM00, 01, 02

[Farqui]

Well done thus far John 

I wasn't sure what that switch was and presumed it would be on the standard cruise control stalk but after a quick Google it seems it's separate;

OEM prices are eye watering, as you'd expect...

[LexIS200Sport]

37 minutes ago, ColinBarber said:

84250A SWITCH ASSY, STEERING PAD 84250-30400-C0	PRE-COLLISION SYSTEM-MILLI-WAVE RADAR TYPE, BLACK, TRIM04, 1*, 2*
84250-30400-E0	PRE-COLLISION SYSTEM-MILLI-WAVE RADAR TYPE, ORCHID BROWN, TRIM00, 01, 02

Those are part numbers for the facelifted steering wheel. I believe John's car is pre-facelift, in which case the the part number for the distance control toggle switch is:

84244-30121-C0 for black steering wheel

84244-30121-E0 for "orchid brown" steering wheel

 

[Britprius]

1 minute ago, Farqui said:

Well done thus far John 

I wasn't sure what that switch was and presumed it would be on the standard cruise control stalk but after a quick Google it seems it's separate;

Hi Lee. Yes that is the distance control switch, but for the later model than my 2007. The switch on my version is a flap that sticks out just below the speek, and display buttons to the right of your red arrow. There is a cutout or knock out line where the switch should be.
I can find a number of complete steering wheels on eBay for £75/100. It may be worth finding the price of a new switch. I could drill a small hole in the back of the steering wheel and fitt a micro switch out of sight for the moment or even put a switch in the little pull off cover for the airbag fastener.

John.

[LexIS200Sport]

@Britprius, the stalk that toggles the cruise control on/off is also different for cars with ACC - you push the stalk forward (away from you) to toggle between radar cuise mode or normal cruise mode. The part number for that ACC toggle switch is: 84632-58011

 

[Britprius]

1 hour ago, LexIS200Sport said:

@Britprius, the stalk that toggles the cruise control on/off is also different for cars with ACC - you push the stalk forward (away from you) to toggle between radar cuise mode or normal cruise mode. The part number for that ACC toggle switch is: 84632-58011

 

Thanks for the heads up Ganesh.
I have just been out to my car and checked the switch, and it is the 58011 switch that is fitted as is the wiring. This grounds a terminal when operated on the newly fitted ECU.
It is possible "not in my ownership" that someone has replaced the switch due to it being broken off something I have nearly done myself if I have left the steering on a righthand lock.
I had wondered in the past why the stalk had an away movement with no operation. Still one less job to do. The switch is only circa £10 new, and fits many Toyota vehicles.
I will add this to the final fitting instructions as an additional requirement.

John

[LexIS200Sport]

No problem, really keen to see how this progresses 🙂

 

1 hour ago, Britprius said:

I can find a number of complete steering wheels on Ebay for £75/100. It may be worth finding the price of a new switch. I could drill a small hole in the back of the steering wheel and fitt a micro switch out of sight for the moment or even put a switch in the little pull off cover for the airbag fastener.

You could get that SE-L steering off the bay and then list yours up for sale for probably the same amount  😁

 

[Britprius]

1 minute ago, LexIS200Sport said:

No problem, really keen to see how this progresses 🙂

 

You could get that SE-L steering off the bay and then list yours up for sale for probably the same amount  😁

 

That's an idea but I rely think the chance of selling a steering wheel is minimal. I will check on the price new of a switch. Going by the price of the cruise control stalk switch it possibly will not cost much. I am sure I can make something work buy cutting around the knockout plastic on the steering wheel but leaving the top edge to act as a sprung hinge. Then fitting a micro switch behind it making it look OEM.

John.

[Paul Brooksbank]

That is really good work and commendable. I can turn my hand to most things but electronics baffle me. I did however find my distance control switch, it looks like this....

 

 

[Britprius]

Is that off a horse, and cart?  must be an antique.

John.

[Lexusls400 =)]

Any updates Britprius? Very interested to know if this worked.

[Britprius]

2 hours ago, Lexusls400 =) said:

Any updates Britprius?

Not as yet I am still working on it, but other things keep getting in the way not leased the weather. This week I have had a very large beach tree up routed, and blown over wrecking three apple, and two damson trees at the bottom of my garden. The trees roots were in the side of a 12 foot deep bank down to a stream that forms my boundary. Only having a root system to one side, and in full leaf the wind pulled the roots out of the bank. Pictures to follow.

I will keep this post updated with all the details on the distance control.

The upside "having just paid for two loads of logs for the winter heating" is I now have enough fuel for at leased six years if not longer.

John.