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View Full Version : Changing a light in the Vent/Heater Control unit


jmoller99
04-15-2010, 03:41 AM
I had a bulb out in my 2002 Frieghtliner vent console. To change it (once you have the module accessible), unplug both wire cable connectors to the unit.

To access the bulbs, you need to open the vent unit up. That is done by gently prying the 8 tabs (4 on the top, 4 on the bottom) open a little and sliding the top cover off a little at a time. When you have it off, you will see some clear plastic light guides, along with 2 light bulbs (sorry about the picture of that being out of focus). The bulbs are attached to a ceramic holder which mounts/turns on the circuit board, and then is pressed out the bottom of the printed circuit board (not easy to do, things are in the way). The bulb in the middle was bad on mine. I found a bulb that is the right size, but does not have the right base on it (my replacement bulb is a type 74 - these are used in my Jeep Cherokee for the same purpose).

On the red card: The bulb on the left is the original, the one on the right is the 74LL bulb.

I improvised a solder job (using a jewelry soldering iron - 700 degrees F, and soft silver solder), as my regular electronic soldering iron would not get hot enough to stick solder to the metal parts of the ceramic holder.

These special plastic bulb holders need to be used because they connect copper traces on both sides of the circuit board together (and if you don't use it, the lights don't work at all).

Any ideas where to find the right tiny bulb for this? I'd rather use the right part if possible (or replace with ultra bright LEDs).

rlent
04-15-2010, 03:55 AM
To access the bulbs, you need to open the vent unit up.
In my 2006 those cups that hold the bulbs are accessible from the back with a pair of needle nose pliers - it's not particularly easy, but it can be done without taking the unit apart (you have to unscrew and remove the ATC unit but you do not have unhook the control cables)

Any ideas where to find the right tiny bulb for this? I'd rather use the right part if possible (or replace with ultra bright LEDs).
Dealer - the Dodge part number is 5133468AA

Cost was a little over $1 per bulb.

jmoller99
04-15-2010, 01:59 PM
The 2 cables I refer to are electrical plug ins, not the vent control cables (I would avoid doing that). I don't have any access holes in the back of my vent control unit to remove these bulbs from. It was likely changed on newer versions of this control box.

Thanks for the Dodge part numbers - I will go get some today.

jmoller99
04-30-2010, 03:13 AM
I finally got my bulbs. Here is where you access them from underneath the control (its not fun to remove). A small flat head screw driver will allow you to turn the bulbs (you may have to move around the vent control knob to get better access.

maxextz
09-16-2010, 03:23 PM
i tried to change mine but as with most things "brake light switch":rant: it was very fiddly and i broke mine and couldnt find any bulbs to fit.

also my light deflector"guide" was burnt and melted where the bulbs sit:wtf: so i need to get a whole new heater unit as you cant but just that part and a second hand one will most likely be damaged also.
what was the condition of yours its hard to make out in the pics.