How can I find the wattage of a car indicator bulb?

FrankFalcon

Hi all

I might say some things wrong here so please forgive me.

I have a business that has 3 vans all the same make (Boxer/Ducato/Relay).  Last year one of my own vans slightly bumped another of my own vans in our own yard.  The only damage was the wing mirror on one of the vans.  Peugeot main dealer wanted over £400 to replace the mirror but I got a new replacement from Peugeot spares (Stellantis) themselves for £60.  So, I fitted the new mirror and bulb but after that the Internal indicator (shown on the dash) flashes very fast, whereas the external indicator works fine.  So, I went on a few Citroen/Ducato/Relay forums and a few people said that this happens when the bulb you replace is of a different wattage to what it should be.  So, yesterday, I went directly to Stellantis and bought 2 new bulbs.  However, the problem is still there.  So, I checked the fuses I bought on the Stellantis Invoice and it says they are 5W.  Indeed, in the forums it is noted that they could also be 16W.  So, what I want to do is go to another of my working vans and see what wattage bulbs are in that van but I don't know how to check the wattage of a bulb.

I hope this makes sense?

Thanks all.

Eldi_Dos

Could you take bulb from your other van and fit in the mirror that you replaced, if the problem resolves it is then a case of getting correct bulbs.If it does not solve problem and the fast flashing on dash persists it may be that your new mirror and van are not correctly connected.

casper_gutman

If these are old school incandescent bulbs as opposed to new-fangled LED thingummies, then I think the indicators are most commonly 12V, 21W bulbs like these: RING PRO Small Bulb 581 PY21W x2 | Halfords UK

5W bulbs are mostly used for providing a general glow, in a tail light. 21W bulbs are typical for bulbs that provide  a more aggressively noticeable signal, such as reverse lights, fog lights, brake lights and indicators.

ETA: Just realised if the bulb is associated with replacing the side mirror it may well be a different type, e.g., one of these: OSRAM ORIGINAL 12V, WY21W, 7504-02B, Glass Wedge Base, Halogen Signal Lamp, Double blister : Amazon.co.uk: Automotive, but I'd still guess at it being 21W. If you look at the photo of those Osram bulbs they're engraved "12V WY21W" . The underlined part is the power rating/wattage. The bulbs in your working vans likely have similar markings.

Andy_L

If you can take the bulb out it should be written on the side and/or it will have a part/serial number you can look up on the interweb

Rodders53

I find that bulb ratings and types are almost invariably listed in the vehicle handbook.

Dig that out and have a look see?

Most lamps have bolts and wattage ratings marked on them.  On glass wedge bulbs it is printed on the glass.

https://tnvparts.uk/products/right-wing-mirror-indicator-blinker-16w-amber-citroen-relay-boxer-ducato-06 says there are two rating types... 16 Watt and 5 Watt.   So you may need to go back to the parts supplier for advice and clarification...  A 16W lamp in a housing and lampholder designed for 5W will probably overheat.

Hilariously that link list the lamp as WY5W which is a wedge yellow five watt one.

Note that a WY16W lamp is larger than a WY5W, so easy to tell apart.
https://www.halfords.com/motoring/bulbs/958-wy16w-car-bulb-manufacturers-standard-halfords-single-pack-722631.html
and
https://www.halfords.com/motoring/bulbs/501a-wy5w-car-bulb-manufacturers-standard-halfords-twin-pack-718332.html