P21/5W BAY15d 21/5w 12V BOSMA bulb

VERY COMMON BULB FOR TAIL LIGHT - BRAKE LIGHT

P21/5W Bulb

Base: BAY15d
Type: P21/5W
Power: 21/5W
Lumen: 440/35 lm
Voltage: 12V
Specifics: 2 offset pins - 15mm base - 2 contacts

References from other brands:
Philips: 12499
Osram: 7528
GE: 1077
Ring: R380

P21/5w bulb

This is the most common bulb for tail and brake lights. It is a double filament bulb. One 21W filament for the brake light and one 5W filament for the tail light. It has a BAY15d base. This is a base with a 15mm diameter and 2 pins that are offset (side view).

   

P21/5w Bay15d

The base of this bulb will not fit into the turn signal socket. Most turn signals use BA15s bulbs, also known as P21w bulbs. This is a bulb with symmetrical pins and only one filament. Bay15d bulbs always have double filaments with offset pins. The offset pins prevent incorrect installation of a double filament bulb where a single filament bulb should be, and vice versa.

P21/5w osram

The P21/5w reference from Bosma with reference number 501214 is interchangeable with an Osram P21/5w bulb, number 7528.

P21/5w Philips

P21/5w bulbs are all identical in terms of dimensions, base type, double filaments, etc. The real difference between brands is quality. Bosma bulbs meet the same quality requirements as Philips bulbs. You can swap a Philips P21/5w bulb with reference: 12499 for a Bosma P21/5w bulb (501214).

P21W - P21/5W difference

The difference between these 2 types of bulbs lies in the pins and the filaments. A P21w BA15s bulb is a bulb with symmetrical pins. A P21/5w bulb has pins that are offset in one direction (side view).

The second difference is that the P21w is a single filament 21W bulb for turn signals, rear fog lights, and 3rd brake light. The P21/5w has 2 filaments; one for the tail light (5W) and one for the brake light (21W). This is the most commonly used bulb for tail/brake lights.

P21/4w or p21/5w?

Both bulbs are used for tail/brake lights. To properly identify these bulbs:

• Look at the wattage marked on the bulb. It must match the 2 numbers.

• Is the wattage no longer visible? The difference between the 2 bulbs is in the pins:

The P21/4w has pins offset in both directions, while the P21/5w only has pins offset in the side view. You can find a list of cars with P21/4w HERE.

For our entire range of P21/5W bulbs, click HERE.