Headlight symbol says headlights on - but no headlights on 2006 Prius

Hi Prius members,

Went out with family for a bite with a few hours of day light left for the day. Started my 2006 Prius to head home and I noticed both head lights on my 2006 Prius would not go on. Luckily I was only a couple miles from home. The headlight symbol on the dashboard shows the lights are on when I turn the lights on, but the headlights do not go on. No high beam - No regular beam. I believe the yellow parking lights are on.

The only other thing I can report is I had the spark plugs changed a week earlier at 120,000 miles and the mechanic put in NGK instead of the Denso that was the part he removed. My Prius seemed to struggle more
with these new plugs or rev more and I am not sure if this affected things, but thought it was worth noting.
I replaced one of the head lamps within the last 6 to 8 months that was going on an off, but this time
it's different with both headlights out at the same time.
Thanks in advance

 

Thank you Patrick. Was wondering if a picture is available of this area which sounds like is under the engine hood.
I looked at the manual and the 40A Head Main covers the following listed below. If wireless key entry works and I can lock doors with
my key fab, which the 40A appears to also handle, does this mean it may not be the 40A Main Head fuse?

Automatic Light Control
Headlight
Headlight Beam Level Control
Light Auto Turn Off System
Smart Key System and
Wireless Door Lock Control (w/ Smart Key System)
Theft Deterrent
Wireless Door Lock Control (w/o Smart Key System)

 

is the main relay/fuse box in the engine compartment?

 

Hi everyone - I popped the hood and removed the fuse over. I check the 15 and 10 fuses and they were ok.
I saw the 6 inch or so clear top white like plastic box. It looks like the cover comes off, but I can see through
the top. There appears to be a wire in each of the squares - some straight, some look like a partial 1/2.
I do not see any burned marks. Can I ask what I should be looking for when checking or looking for.
Does the cover come off? Does each square contain a removeable fuse like the way I am able to pull the
a 15 and 10?

To the right of the clear/white long box is a gray square fuse that I believe per the back of the fuse cover
notes fuse for the HL-P Relay. Not sure what to do with this either. Does it pull out? Does just the cover
come off. Sorry to be a pest - need help with the details. I posted a picture to help

 

Thank-you Patrick. I think I got it now. I will post what I find out after exploring.

 

Update - I received my multi-meter and tested the relay. It clicks when 12 volts was applied and when I tested the with the multi-meter the resistance showed it was working. Not sure what to do now. I am not sure if this would work, but I had a left over new bulb so I plugged it into the silver, square socket and turned on the lights and the new bulb did not light. Not sure what to do now. You may recall both headlights decided to not work one evening at the same time. Any other ideas I should try would be appreciated

 

Thank you Patrick. I grabbed my multi-meter, set it to volts and pulled the H-LP relay. The relay is grey and it does not have
the 30 87, 86, 85 numbers or a diagram on it. It does have the part number. I place the probe on the two odd, wider - | and received 12+ volts.
When I probe the two equal || points, there is no volts. This is the relay I tested yesterday with that clicked and the ohm test was ok.
What I did net was I removed the DIM relay below the H-LP relay and I did the same test of probing . My meter showed no volts when I tested
the -| and the ||. I believe I then put the light switch on and tried again with no volts to the DIM relay.

I have to test the fuses as you suggested but in the mean time I have a question on how do I test the bulb socket? Is this the silver square piece that locks over the bulb? As you may recall my light suddenly stopped working but the dash board shows they are on and the blue high beam icon comes on when I put the high beam on. So basically the dash board looks like everything is working, but there are no head lights. The amber lights come on to the sides of the head lights and the parking lights come on and the fog lights work.

Sorry to bug you with this same problem, but hopefully other will benefit from this post.

Thanks,

Jim

 

I went back to completed the fuse test step. First I test if my multi-meter was working property by putting a AAA battery to it and it read 1.62 volts which is good.

I pulled the first two 15 AMP low fuses and turned the headlight switch to the on position. The dash board low beam icon was lit and the amber side lights were on, but not the head lights. I put the probe on each side of the fuse holder and the meter stayed at 0.00 or no power. Basically I put the red and black probe on each side of where the fuse metal tabs plugs or pushes into.

I removed the two 10 AM high beam fuses, pushed forward the column switch so the high beam icon was now lit on the cask board. Like the other two fuses, these two fuses show no power. I removed the horn fuse and the probe showed 10 AMPs of power, which I did not make sure I was testing the fuse sockets correctly and the multi-meter was working.

I went back to the DIM relay which is light blue and made sure the head lights were on. I tested the socket where the relay plugs into the -| pattern and was no power. I tested also the shorter || pattern and this showed no power. I then turned on the high beams and the same, no power to the DIM relay.

It seems from the Patrick's last post that this points to the relay and it's wiring. I would tend to think wiring since there is no power.
Any advise at the point would be appreciated and I am concerned this is now a difficult fix.
The only thing that troubles me is I recently had the spark plugs replaced a few weeks before the head lights went out.
The dealer put in a NGK brand and DENSO plugs were the original equipment that was removed during the change.
The moment I drove the car, my Prius seemed to struggle and whine and I was wondering if the spark plugs could make a difference
and cause an electrical issue. Not trying to blame anyone - just the car did not seem right after the spark plug change and now this happened.

Any advise at this point would be appreciated.
Thanks in advance.

 

Hi Patrick,

I will try to digest your latest instructions but I think I am starting to get in over my head.
I think you would like me to remove the H-LP relay, which is the only relay I received power from and test
where the relay plugs in with the Ohm resistance function. Going from you previous post, you felt it was
the DIM wiring, based not seeing power at the fuses, or where the DIM plugs in. Being more visual, I have to
try a little harder than most to understand. I will keep trying as I feel I got pretty far for a newbie.

 

Hi Patrick,
Sorry for the delay. I pulled the relay and put the meter to the ohms area where there were 5 choices.
The two equal prongs had a reading on 20K and 200 which was ,173 at 20K and 175 on 200.
The reading at 200 bounced from a reading of 175, 173 and 169 on different reads. These are the two equal prongs
the have the || pattern. On the other set of metal prongs of the relay where the pattern was different in size and
direction where they looked like -| the reading was always 1

 

Thanks Patrick. There are a total of 4 metal terminals on the bottom of the H-LP relay. When I use the -| symbol, I am identifying the two
terminals matching terminals on opposite ends where one is sideways and the other is straight so they look like - |

The opposite the - | are two terminals are equal, meaning they look like a regular plug so the look like | | . These two terminals had the -175 ohms reading. The two terminals that are - | had no reading or as you pointed out, infinite resistance.

From my previous post on July 29th, when I tested the sockets the 4 terminals of the relay plugs into, the odd shaped - | side of the relay has 12+ volts and the other two equal terminals showed no volts.


So basically

The shaped - | terminals on the relay had no resistance, but had 12 volts of power at the socket where the relay plugs into
The | | equal shaped terminals have -175 Ohms of resistance and no volts at the socket where the relay plugs into


Tried my best to describe the 4 metal terminals coming from the bottom of the relay I called prongs in my previous post.


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