Hi,

My front indicator bulb blew a while ago. My old bulb was heavily corroded so I couldn't make out the markings, other than 21W. I since replaced it with a bulb GK 12V21W P21W(E4) 2HR, the bulb "worked" but it seemed this wasn't the right part because the indicator was now flashing faster and the light was very dim. It got me home without a ticket at least.

I just switched the left and right handside bulbs and that seemed to fix the problem with the fast flashing, it seems this is the original bulb, the details read: GE 1057 12V P21W (E1) 2DX Hungary 518. From what I can discern, P21W is the fitting type, which is the same as BA15s. E1/E4 is quality indicator, so GE 1057 should be the part number.

Annoyingly, I could not find any information in the Seicento instructions booklet or any technical details in the technical manual I downloaded through this forum. It also seems that GE 1057 has been replaced a long time ago by a new type, but the information I can find on this is pretty confusing to me.

Can anyone here advise me on what replacement bulbs work properly with the Seicento 1.1 1999?

Any 12volt, 21w orange bulb with the correct fitting should be absolutely fine. I will say though that the connections have a tendency to corrode over time, as my driver's side (UK) indicator bulb is very temperamental - sometimes working, often not and producing the fast flashing that you're getting.

A white bulb would be a P21W and an amber bulb a PY21W.

Very std bulb.

I take it you haven't fitted LED versions? Which being a lower resistance would change the flashing speed.
Loosing the side repeater indicator (the W5W capless bulb) would also change the flashing speed.

Thanks for your response. My father in law also thought it might be a problem with the ground connection or corrosion. I also was under the impression that the 21W bulb should just work.

There was corrosion on the contact points, we sprayed this with a cleaning agent. But it just seems like this is not the problem when switching the two bulbs remedies the problem. My hunch is that the "GK" bulb is the cause but I couldn't find any additional information on this bulb's technical specification or how it differs from the OEM part.

I can try out an orange bulb as you suggest. I haven't fit any LEDs. We checked and cleaned the side indicator as well, it seems to be in correct working order.

Thanks for the help guys. It seemed this GK bulb was the culprit, eventhough it was a 12V 21W bulb with P21W fitting. I tried two of these bulbs from the same package and they had the same problem, so that excludes (for me) that it was a problem with a specific bulb.

I went to the petrol station and bought a Philips P21W bulb, with E1 quality mark. The light is nice and bright and the fast blinking problem has gone. For future reference, the markings on this bulb are: P21W 12498 PHILIPS 12V 21W (E1) 2CH / 46 '17.

Seems like maybe the 'quality' (E1-E4) might have been the issue then.

After a bit of quick Googling.
E1 just means it was tested in Germany and E4 just means it was tested in The Netherlands.

Thanks for correcting that, David. I think I got the information off an American site before. The last bulbs I got were designed in Germany and made in Poland. Interesting how these products move around.