How do you replace heater control illumination bulb on Volvo s40?

Answer 1

Here is how I replaced the three bulbs behind the heater/ac panel on a 2003 Volvo S-40. There may be some variation for other model years and types, but there may also be similarities.

1. Prise off the cover panel with a small, flat-blade screwdriver. This may take a little persistence, but there are no fasteners retaining this part; only small plastic ridges at the rear. The round dials stay in place.

2, Once this panel is removed you will see four phillips screws retaining the control unit. Remove these and set them aside in a safe place. Now you can push the unit in, and begin to rotate it to the side. The multi-pin plugs and the air sensor tube should be to your right.

3. Remove the multi-pin plug closest to you first. This is the smaller of the two. It may take quite a bit of wiggling and pulling to get this plug off, but it will eventually give up if you keep at it. There is no release tab that I could find. Then remove the air tube by pulling and turning it. This was difficult for me, but it finally came off. Finally, remove the multi-pin plug at the rear, again by pulling and wiggling. Not really easy.

4. With the connectors and air tube removed, you can begin to work the control unit out of the dash. It barely fits through the available space, and removal is complicated by the centering channels molded at the front of the unit. It's just a matter of carefully working it out. Be very careful with the control unit and the circuit board therein. If you drop it, the game may be up.

5. Now you can work on the control unit on the kitchen table, where you have good light. You can see the bases of the bulbs through molded tubes on the back of the unit, and it may be possible to change the bulbs using a needle nose pliers, but I recommend removing the four small star-head screws securing the back so you have the circuit board fully exposed. With the back removed, it is easier to carefully remove and replace the bulbs, though a needle-nose may still be necessary to rotate them a full 90 degrees after insertion. Slots are provided on the bases of the bulbs for this purpose.

6. I purchased new bulbs from my Volvo dealer (part No. 30618412). Sorry to say they cost $18.86 each.

If you had a lot of bulbs burn out, it might be cheaper to buy a new car with new bulbs installed.

7. These bulbs are not diodes (which would be polarized), but ordinary little mini-bulbs with blue latex covers. After they began to burn out toward the end of year No. 8, it occurred to me that I might have extended their life by reducing voltage with the dimmer control next to the headlight switch. I have always kept the dimmer switch at max, and the dash panel lights are on whenever the key is on and the the vehicle is in operation. I read on a website that identical bulbs can be purchased cheaper from a Honda dealer, but I can no longer find that website or the Honda part number it supplied.

8. We bought this car new in February '03, and it now has over 100,000 miles. It has had good maintenance (including synthetic oil), but has given us almost zero problems. I have done two brake jobs (just finished the second), and replaced tires once. Appearance, performance and handling are just about like new. Fuel economy is way better than advertised on the sticker. My wife thinks I have no right to complain about these pesky little bulbs.