Failure Symptoms:
One or more rear lights do not work. Or you get annoying messages telling you that one or more light bulbs are broken (but they actually work just fine).
However, this guide will focus more on what type and where the different rear light bulbs are located rather than how to change them.
5 Series (1988-1995)
floor jack, jack pad liners, jack stand, screwdriver (flat-blade), wheel nut wrench (17 mm), tire lever (or similar), brush (small steel/brass), ratchet wrench, torque wrench, brake pad spreader, socket (7 mm Allen key), anti-seize compound (Loctite 8009 or similar), brake cleaner (CRC Bräkleen or similar), micrometer (0-25 mm)
The following tools are required for this particular work (tools marked with green checkmark are optional).
 | Phillips screwdriver | |
| | flat-blade screwdriver |
The following spare parts are required for this particular work (parts marked with a green checkmark are optional). Note that the BMW internal numbers are intended for a BMW 535i E34 -89.
| | P21W 12V BA15s light bulb (8 pcs) |
| | R5W/R10W 12V BA15s light bulb (2 pcs) (Germany/Sweden) |
Walkthrough
The rear light bulbs are easily accessed from the trunk. Simply remove the rear-panel trim after opening the quick-release fasteners. In Picture 1 you can see the location of all the different rear lights. Further down I have also listed what type of light bulb that are used in the different rear lights.
Picture 1 : The location of the different rear lights.
- Reversing light (Rückfahrleuchte)
- Rear fog light (Nebelschlußleuchte)
- Turn indicator (Fahrtrichtungsanzeigeleuchte)
- Brake light (Bremsleuchte)
- Rear light (Schlußleuchte)
- P21W 12V (BA15s)
- P21W 12V (BA15s)
- P21W 12V (BA15s)
- P21W 12V (BA15s)
- R5W/R10W 12V (BA15s) (Germany/Sweden)
Only two different types of light bulbs are used at the rear, the so-called P21W BA15s and the R5W/R10W BA15s light bulbs.
The P21W and R5W/R10W notations define in which category (in the European ECE R37 and American SAE regulations) the light bulb belongs. The first letter defines the shape or type of the light bulb. It is followed by the power rating (in watts) of the light bulb.
Take the P21W for example, the letter P says it has a pear shape and a rating of 21 W. Below you can see a list of the most common shapes.
- P = Pear
- PY = Pear Yellow
- R = Round
- W = Wedge
- WY = Wedge Yellow
- T = Tubular
- H = Halogen
- C = Cone
Sometimes you can come across a light bulb called P21/5W. It’s actually two light bulbs in one (it has one extra filament and contact point compared to an ordinary light bulb).
Picture 2 : Picture of the most common light bulb shapes.
Picture 3 : To the left is a P21W bulb and to the right an R5W bulb.
Picture 4 : A W5W bulb.
The second expression, BA15s, defines the socket type. All light bulbs at the rear have the so-called BA15s socket. The P21/5W light bulb mentioned earlier often uses the so-called BAY15d socket. It differs from the BA15s by having two contact points at the bottom but also the bayonet pins are slightly offset. In Picture 5 and 6 you can see what the BA15s and the BAY15d sockets look like.
Picture 5 : A BA15s socket.
Picture 6 : A BAY15d socket.