Headlight leveling sensor DIY repairs - have they held up?

Those harness wires from the back to the front have < 10 ohms resistance, so the ECU won't know the difference as to where the pot is located.

 

Has anyone done the potentiometer installation in the instrument panel? I thought I could get this fix done on my daughter's 2005 Prius (sensor is toast...arms were broken off). I got that connector off and sealed up, and built up a small project box with the 5K pot and the 20K resistor (very close to 0-3.9K pot now), wires ready. Planned to just use the crimp-style splices on the wires near the headlamp leveling ECU connector H12.

But, I have not been able to locate that connector. The diagram on page 46 in the wiring manual shows it behind the glove box area, but it looks different than that diagram, so I cannot be sure which is H12.

Has anyone done this and taken pictures they could share?

Thanks in advance!

 

Here is a gif of H12:

 

I repurposed the old corroded leveling sensor into a connector for my potentiometer fix. I destroyed the sensor carefully to recover the connector portion and wired the potentiometer to it using solder. I wrapped the assembly in black electric tape and positioned it in the left side cubby hole in the "trunk". This modification has been working fine for six months now.

Now, if I want to return to a stock leveling sensor, I just unplug the potentiometer assembly and plug in the new leveling sensor.

This is quite easy to do and can be returned to completely stock with just a new leveling sensor.

 

I found the wiring diagrams with these connectors, plus the line drawing showing where H12 "should" be, but was not certain if I was looking at the correct connector... I would have guessed the lower left connector in this shot, but yellow wire is on the end of a 22-pin connector, but diagram says yellow wire goes to pin 20. I had limited time to dig into this, and did not want to take any chances.
Can anyone identify which connector is H12?

 

For people looking into this mod, I can tell it works great, cost me 3$ for a pot and knob and it doesnt get better than this. No more warning

For people who might be interested:

You will need a 5k ohm potentiometer and knob if you need it clean and pritty
I hide mine in glove box

As in picture posted by 500VDC you need to go to the plug on far right. Harness connected on a small black box above ground plug.

Yellow is
Pink is 5V reference
Blue is signal for module
You will need to connect yellow and pink on extremities an blue in middle


You will also notice there are 2 blue wires on plug, we are using the 1 on same side as pink wire

This site has helped alot for this issue, if someone needs help please send message

 

exactly!

 

Thanks for the explanation! Did you try putting a resistor in parallel across the pot? I don't see why this would change the way the circuit works. I googled up page 05-1738 of the manual and it seems to be saying that when you put 4.5v between pin 2 and pin 20, the voltage from pin 5 to pin 20 should vary between 4.5v and 0.5v. This makes me think that if you have a 5k pot, the thing to do would be to put a 620 ohm resistor between the pot and pin 20, so that the voltage at the center lead of the pot never gets too low.

I would like to try this --- if I can figure out how to get to the wires behind the glove box (or wherever they are) in the picture posted by 500VDC. I've googled around but haven't been able to find this information. I'd love it if someone could tell me how to find out this kind of thing. This is my first Prius repair attempt. This thread has been incredibly useful, but I'm stuck on the most basic things!

 

You are exactly right. Remove the lower glove box for access.

Oh - you don't know how to remove the glove box? Open the glove box and empty its contents.

Find the damper on the far right of the glove box. Note how it is attached, take a photo if necessary for reference.

Then use your right hand to pull the lower end of the damper off its mounting pin. Use your two hands to squeeze the glove box sides inwards, so that you can lower it. Pull the glove box out and away from the pivot.

Now you have access to the cabin air filter (the right edge of which is visible in the photo) and also will see the ECU wiring as in the photo.

Consult techinfo.toyota.com for an electrical wiring diagram and for factory repair manual info.

 

On a related note.... Now there is an aftermarket option for the rear sensor.
Often costs less than $100.
Stop by your local parts store and ask for it

 

Can you provide a little more detail about the aftermarket sensor? Specifically, the auto parts store that sells it (Advance Auto, Autozone, etc) and the manufacturer of the part (if you know it).

Those of us who have had our share of grief with it have been patiently waiting for a less expensive fix.

Now if there were only a brand new aftermarket traction battery (lithium ion even) for the Gen 2 and 3 for $1000, wouldn't that be nice!

 

Sorry I don't have the detail.
The one parts store in my small town is not a national chain, but they carry it. It's a Dorman part. So if it's available here, it's available anywhere. Just call any parts store and ask for a "headlight leveling senor" for your year Prius.

As I mentioned in other threads, for Honda, aftermarket new cells have been available for several years. There are aftermarket new cells for Prius but they haven't been around long enough to confirm their reliability yet. So although I can have them in my hands I am not selling them to customers. They are not $1,000 and they will likely never be $1,000.

 

Thanks much, e. The Dorman replacement is very reasonably priced.

Dorman part number 924-755. $63.46 shipped from Amazon.

 

You might want to try your local parts store, too.

May be slightly more expensive, but nice to shop locally once in while.

 

I mainly wanted to share the part number with everyone. Amazon more often than not has good photos of what you're buying.

 

Replacement sensors for under $20 on ebay; as I cannot post links yet, search for sellers by the names (dtpd-auto-diesel-parts-wholesale) or ( automartin914) !

 

Hoping to revive this thread , would someone kindly help me find a solution for my 2010 ? Do you think the same 5K potentiometer would work on this one? I cannot find anything for the headlight levelling sensor on the gen3 other than it’s a $300 part... Not only that but the warning light is extremely obnoxious flashing ⚠️ and taking over the whole display.. thank you very much