How do i check third brake light?

[96_sport_ct]

i know how to get to the ballast now, thanks to the forum, but how can you tell if it is the light that isn't working or if it is the ballast? i have a multimeter to check voltage out of the ballast but i do not want to attach it because i want to know how much power is supposed to be coming out first before i try so i only have to take everything apart one time. i have yet to test to be sure that voltage is good before the ballast since i don't have someone here to push the brake pedal but the other rear lights work with no problems. if anyone can upload a picture or a video or give me detailed instructions on how to test it would be much appreciated.

PS- i want to try the least destructive way possible so if i can test without having to drill out the rivets to get the rear light out it would be much better.

 

[gmanpaint]

Have you tried to clean the trailer harness connector yet?

I went threw the exact same thing as you with this, in fact, it is the reason I joined and became elite. The $$ saved by just cleaning the trailer harness instead of throwing money at good parts was well worth the $20 to go elite to repay this forum

 

[96_sport_ct]

what do you mean by that connector? the connector plugging into the ballast at the top of the hatch or do you mean a different one?

i would also join elite but i dont have the money. ive used this site for years to look up information but only recently joined. i plan on joining elite as soon as i can get the money together seeing as how im broke right now.

 

[gmanpaint]

I was not insisting, its up to you when you can go elite. It's all good.

There is a round connector behind the drivers side tail light. You have to disconnect it, and clean it with a electrical contact cleaner.

Lay on your back under the rear bumper and look up behind the tail light. You will see the gray connector. Unplug it. Have someone step on the brake pedal, or back up to something that will shine a reflection. If the 3rd brake light comes on, clean the connector, and plug it back up.

Water & dirt gets in it from road spray and what not, messing up the tail light.

Post back with any results please.

 

[96_sport_ct]

so what does this connector control? are you saying to clean it then re-connect and test or unplug it then test?

 

[gmanpaint]

Unplug it, step on brake, look for 3rd light working or not. If it works, clean it, plug it back up.

If it does not work after plugging it back up, but works unplugged, leave it unplugged. It is for the trailer harness hook up.

 

[96_sport_ct]

didnt work. i think i had the correct connector. is it the one that you can visibly see from inside where the tail light goes. i follower the wire and it connects to the license plate lights.

btw even if it doesnt work, i at least got the joy of waking up the neighbors to pull into the garage since the truck has no muffler

 

[gmanpaint]

The connector is not inside the rig. It is outside. Only way to get at it is by laying on the ground on your back. Look to the far corner on the drivers side. Now look towards the direction of where the tail lights are. Reach up and feel for the connector. It is about 1.5" around. Gray in color. Has a bunch of wires on it.

 

[96_sport_ct]

im going to try and get a picture of what i tried and ill put it up here

 

[96_sport_ct]

lets see if it will embed this time. the connector on the bottom that i am not touching is the one that i tried disconnecting

 

[gmanpaint]

Nope, thats not it. It is a ROUND connector, bigger than the one your referring to.

Whats the model of your rig? XL, XLT, Limited, etc...

Do you have a towing package? Do you see a trans cooler in front of the radiator?

Did you look from underneath? It will be behind what you can see in that pic. You just wont be able to see it by removing the tail light.

 

[96_sport_ct]

96 explorer sport with control trac 4wd. 4.0. there is a trans cooler in the front that is at about the height of the front bumper. only has a single ball on the rear bumper nothing special.

 

[gmanpaint]

OK, it should have a tow package on it. This means the connector for the hitch harness should be there.

 

[96_sport_ct]

if its supposed to be coming out of the wiring harness for the drivers side brake lights that is the only connector. i went under the truck and there are no other access panels on that side. the only lights that arent in the tail light are the license plate light. i dont see any connector for a trailer at all in that area. can you get a picture so i can see if maybe i am just not seeing something

 

[gmanpaint]

I never said it is connected to the brake lights where you are looking.

I said the trailer harness. Get a Chiltons book. Look it up.

 

[96_sport_ct]

yeah i looked. that connector is a dumbed down version of a trailer harness. that connector there is the only one on that side in the rear. does anyone know how much power the ballast is putting out? i want to test power but if its really high i want to know so i can prepare for it because i dont feel like having to worry about getting seriously electrocuted

 

[ash98fordexp]

my 98 xlt has the trailor package but the plug gmanpaint is talking about is behind the driver side break light. i just pulled my light unit out and there it was after pullling it up some...

 

[96_sport_ct]

yeah, the same grey plug as in the picture. the only difference is that mine doesnt have the wires for that but i could just change the wires out with the towing wiring harness

 

[ash98fordexp]

well mine is a big round plug.. almost as big as the bulb in the pic so urs must be different then what is in mine. mine has its own plug for it if i get around to it ill get a pic to show u what i am talking about

 

[budwich]

you can't test the ballast with a multimeter due to its nature. Yes, you can check to see if it is getting the proper input voltage but that's it. The output is based on a "properly terminated discharge based load" (ie. a good bulb or "equivalent load"). Further, IF you play around with the ballast "improperly", you can damage it and / or get a "nice surprise" along the lines of lots of volts.

Having said the above, yes you should check for correct input voltage, that will likely point you in the direction of a wiring issue as has been suggested in the area of the plug.