Troubleshoot a HID headlight

In general, an HID headlight problem is attributable either to the bulb or the electronics module. To ascertain whether the bulb is the problem, the normal approach would be to swap bulbs from side to side.

However you'll probably find out that it is not easy to remove the bulbs, so you may decide it is easier just to install a new bulb and see what happens.

 

There are many, many threads on HID failure and replacing the capsules. Search for HID.

Tom

 

If the light won't come on at all, even when you switch the lights off and back on, then 99% of the time the bulb is bad. I would just replace the bulb. Keep the old one for awhile just in case though.

Regards,
Dave

 

If he got any skin oil on it, that could be why it went so soon.
.
_H*

 

your supposed to be getting 85 volts AC out of it, but i wouldnt risk powering it up to measure the voltage, if the bulb doesnt work in the other side headlamp then the bulb is bad, I bought a set of D2S bulbs on ebay, 5000K for about 60 bucks, one of those noname brands, and its been roughly 40k miles so far and no problems.

when you are ready to install you cannot touch the bulb at all, you must prepare the headlight to install the bulb then you can just install it, i suggest you replace both if your buying a new set of bulbs because new HID bulbs need to be burn in.

 

I have no experience of the specifics of the HID driver circuits on the Prius but I have mended lots of projectors that use metal halide. You cannot measure it with a voltmeter, it will likely fry your meter. Do be extremely careful, they hurt when they bite you. The only way I have found to look at them is with an oscilloscope and even then the waveforms off load are little indication of the waveforms when there is a bulb connected.

Testing by replacement is by far the easiest way.

 

Terry

So, I'm wondering why a guy with a '08 wants to try to fix his HID himself, as that's what the warranty is for, then noticed you're in Red Deer, Alberta.

As no Canadian market Prius was offered with HID, you must have picked up yours in the States. Thus, no warranty

There are a few threads here about HID problems. I'd also suggest a subscription to All Data DIY

ALLDATAdiy.com :: Leading Source of Diagnostic and Repair Information

A one year subscription is under $20 and you have access to the same factory service manuals as a Toyota tech.

I should warn you that if you're stuck paying for parts, this could get pricey

jay

 

A salvage with body damage.... then I'd ignore all the previous suggestions. Start looking the the areas that had the body damage for wiring damage. Check fuses.... check the INPUT voltage to the lamp ballast to see if it's getting 12V.

 

Again from mending projectors, the bulbs rarely blow as in working one minute, not working the next. They get dim and start flashing but usually they still strike occasionally. Have you tried looking at hte light while soemone else turns it on. Often they will strike then go out but that will not tell you whether the bulb is the problem or the driver circuit, it merely tells you that power is getting there.

 

About the same here

A complex vehicle like a Prius can be a nightmare when it fubar's

Oh .... sure ... yeah, right ....

 

does the smack test work? (smack the headlamp assy, see if it comes back)
does it start at pre-start (low glow, first 5 sec or so)

this is copied over from a previous post on HID failure- it was a general comment but not intended for someone to use to diy test anything.

the headlight computer (ballast) has 2 wires going into it for the headlight. if, when the lights are turned on, there are 12v in the wires, the problem is either the computer or the wire between the computer and the light. if there isn't 12v in the wires, it's a problem with the wiring in the car, the headlight relay, or the headlight switch.

and an extra note for your safety:
unplug the wiring harness that leads to the headlamp assy. test the 12v wires that plug into the assy. do NOT test at the headlamp side. those yellow high voltage stickers aren't kidding, those can lay you out.

with a salvage vehicle, always assume body wiring first. this saves a lot of money in peripherals, like bulbs and headlamp assemblies. and as always, safety first.

 

Terry

How does it look underneath? I've seen salvage cars that looked cherry topside, but underneath it's such a butcher job on the unitbody and pieced-together wiring, you want to run away screaming

jay

 

Years ago my dad was looking at a used Triumph sports car. It looked great, and the price was very attractive. He took it to a mechanic for a once-over. The mechanic looked underneath and said: "Wow! I've never seen Bondo on a frame before." Not a good sign.

Tom

 

I hope your pops ran away screaming ...