I know there are threads that have discussed this but as far as I know no one has ever succeeded in getting an EV switch installed and working in a rx400h. I think I am close to figuring out how to do it. I do need a little help. I have access to Chilton's online library, but as far as I can tell, there is no page that will show a connector and list all the pins/wires and what they do. Is there any way to get this information? Looking for a pinout for H29 connector on a 2008 Lexus RX400h.

 

Try to find a wiring harness diagram for the second generation Toyota Highlander Hybrid with the same 3.3 V6 as the RX400h. They do come with an EV and Economy mode, even everything else seem to be similar to the RX400h.

 

thanks for the tip. I already found a diagram for the 2nd gen hihy and identified what wires do what, but I would like to find a pinout for the rx400h or 1st gen hihy to be sure they share the same wiring.

 

Would you like to share that diagram with me? I'd like to think along with you. I'm brainstorming for a similar conversion already for months now.

 

I found the following differences in the wiring between RX400h and Highlander Hybrid (2009). The list shows what one model has that the other does not and what I believe the function to be:

RX400h:
PR2 (a/c pressure switch/sensor signal)
HP (a/c pressure switch/sensor signal)
TAM (ambient temperature sensor signal)
BS1 (rear circuit breaker sensor RH +) skid ecu?
BS1G (rear circuit breaker sensor RH -)
BS2 (relay 2 monitor, rear circuit breaker sensor LH +)
BS2G (rear circuit breaker sensor LH -)
TACH
LGND (distance signal, laser/radar sensor)
IGST (unknown, possibly Ignition start, since highlander uses power button ignition)
CCHG (distance control switch signal, distance control ecu)

Highlander Hybrid:
SNWI (ECON/pattern select switch)
EVSW (EV mode switch)

 

In the Gen 2 Prius the retrofitted EV mode switch connects to the HV ECU. Can you look for the HV ECU in the Highlander's wiring diagram and show its pinout list?

 

The differences I noted above are specifically differences regarding the hv ecu. I will post a photo showing the pins used in the highlander for ev and econ. Both are in the right most connector.

 

rx400h pinout:





from highlander hybrid:

 

Are you sure these D35 and D36 plugs plug into the HV ECU?

the ECU looks similar on both the Highlander and the RX400h:

https://m.tlsautorecycling.com/searc...dr/396842.html
http://extreme-auto-parts.com/lexus-...92-89981-48192

are you sure your information is for the MHU48 model as I believe they changed to the newer 3.5L motor around 2009, which might have introduced a different HV ECU.

 

yes, they plug into the hv ECU, and correspond with the h29 and h30 plugs of the rx400h. The highlander hybrid did not get the 3.5L until 2011.

 

I haven't a clue what you guys are talking about but i'm interested to see what your outcome is. Are you trying to shut the ICE off and run completely on electric? There may be others that are watching this thread but i may be the only one stupid enough to ask. So please keep this thread going.

 

That is exactly it. Most Toyota hybrids have that button from 2008 and newer. It is only good up to 29mph and under 40% throttle, and that is assuming the battery has enough charge and within temperature window. But it allows you to travel short distances without running the engine.

 

I'm afraid to report that grounding the same pins that will give you your EV mode and ECON mode on the Highlander will not work on the RX400h, at least, not on my 2006 European spec.

 

I'm hoping to try this next week on my 2008 US spec.

 

Did you manage to check this?