Idiot Light Bulb Replacement

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Hartge
Posts: 12
Joined: Thu Jan 25, 2018 8:08 pm
Location: Peterborough, Ontario

Idiot Light Bulb Replacement

Post by Hartge »

Well my SI Board showed up from Programa. Fairly straight forward swap if your patient and mind your guage needles.
While in there replaced the 3, 3 w bulbs with sylvania 2825 5'w and the headlight and foglight bulbs with T5 L.E.D's
Also thought I would freshen up the idiot bulbs with recommended sylvania 2721 12 volt 1.2w mico bulb.
Plugged the cluster back into the dash everything worked great but not one 2721 worked.
The original bulbs were really tight and difficult to get out and the new ones are in and a bit sloppy.
Anyone with experience replacing these tiny bulbs? Am I using the correct replacement

Thanks,

Iain
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86_6series
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Re: Idiot Light Bulb Replacement

Post by 86_6series »

If you changed the charging bulb be aware that it's also an exciter bulb to activate the alternator.
Just make sure your charging circuit is working with bulb changing.
86-635CSi
96-MB C220 SOLD
98-740i
71-Continental MK3
Hartge
Posts: 12
Joined: Thu Jan 25, 2018 8:08 pm
Location: Peterborough, Ontario

Re: Idiot Light Bulb Replacement

Post by Hartge »

The alt light comes on with the ignition turned to position one. I did change it to a 5w bulb however.
I need to pull the cluster to replace the micro bulbs. Do you think it’s necessary to put the 3w back in the alt circuit?
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86_6series
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Re: Idiot Light Bulb Replacement

Post by 86_6series »

If the 5 watt lights up with ign on and goes out when engine is running,
test to make sure the alt circuit is charging. If this happens you should be good to go.
If not, go back to 3 watt and recheck system.
86-635CSi
96-MB C220 SOLD
98-740i
71-Continental MK3
Hartge
Posts: 12
Joined: Thu Jan 25, 2018 8:08 pm
Location: Peterborough, Ontario

Re: Idiot Light Bulb Replacement

Post by Hartge »

Thanks for your input.
The alt light does go out once the engine is running with the 5w bulb.
Now to figure out these micro bulbs.

Iain
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