[Ryan001]

I've recently bought some red LED bulbs for my brake lights, but the Saab rear light panels only have these offset pin pattern at the bottom of original bulbs. Can Saabs only use the Phillips red coated bulds that aren't 1157 standard? Have Ice clear rear lights.

 

[okcrum]

Yes.

 

[Scarab95DropTop]

And it’s a PITA. The part stores near me don’t keep them in stock.

 

[EdT]

If you want to try something, you can file off one of the pins. Assuming the bulb socket is decent quality, the remaining pin should locate the bulb okay. I did this on my NG900; however that car also had good quality sockets. If the socket looks flimsy, don't do it.

ETA: since this is an 1157, you have to figure out which of the pins to file off. Otherwise you will have the bright brake light on all the time. The bulb base has two contact points. One of those is for the bright filament, the other for the dim. If you file off the wrong pin, the bright brake "filament" of the LED will be on when the system is intending to just light the taillights.

Hmm, are you sure that the OEM bulbs have two filaments? I thought the NG9-3 used single filament bulbs with PWM controlling how bright they were, at least for the earlier models with tinted lenses instead of the clear ones. If the red bulbs have a single contact point on the bottom, they're single filament. In which case, you need an 1156 equivalent, not an 1157.

Those offset pins are used on a couple of types of bulbs. The red coloured one is one of those.

 

[okcrum]

The combo bulbs that fit the single filament sockets will light only the brighter filament, which is rated the same as the single filament bulbs. I ran into this when I had to change bulbs on mine. It was a little confusing until I looked up the bulb ratings and looked at which contact was making in the socket.

On the plus side, it's handy if only one bulb type or the other is all that's available.

 

[EdT]

The combo bulbs that fit the single filament sockets will light only the brighter filament, which is rated the same as the single filament bulbs. I ran into this when I had to change bulbs on mine. It was a little confusing until I looked up the bulb ratings and looked at which contact was making in the socket.

On the plus side, it's handy if only one bulb type or the other is all that's available.

Yes, that would happen if:

1. It's a filament bulb
2. Both the contacts on the bottom of the bulb have a good contact with the contact in the socket (which is centred in the socket, of course)

Reason is that the bright filament has much lower resistance, so almost all the current flows through it. The dim filament will have some current flowing through it (Ohm's law), but not enough to light it noticeably.

In the case of an LED 1157 bulb, I don't know what will happen, probably the lamp will act as if both "filaments" should be on, which would mean it would sit in its bright state all the time.. What you want is a red 1156 LED bulb. There still may be issues, because if it's a single filament bulb, the brightness is set by PWM. How the LED will react, as well as the car's onboard modules which check for bulb function, I don't know.

I guess the TL;DR is, if you want to experiment, you likely will have to figure it out yourself, and that requires some understanding of bulbs and electronics.

 

[Mimmi]

Rear bulbs are single filament 21W bulbs.
When tail lights are on, REC sends PWM to tail lights, so they lit like 5W bulbs.
When you press brake, REC sends constatn voltage to tail lights.

 

[okcrum]

Understood well, Mimmi. FWIW, both the combo bulbs in my 2011 were in the single filament sockets when I got the car. It's impossible for me to say they'd been there from the beginning, though. It may just be that people use the other bulbs in a pinch, because red bulbs of any type are hard to find locally over here.

 

[Ryan001]

Wow that's for all the support, guess Saabs are just different. LEDs look nice but sounds like they will be a hassle to put on.