Head Lights Dimming

[MrNadin]

hi all have noticed that my head lights on my 03 t-sport keep going brighter then dimmer as i'm driving not jut a bit but quite alot i thought at first it might be the climate control kicking in but it does it even with everything switched off anyone got any ideas??

[Mooly]

It's the auxilliary air pump on the inlet system... it's nothing to worry about. It draws a fair bit of current and pulls the voltage down a little. I used to see it just glancing at the instruments in daylight and sometimes you catch it when it happens...

When you start the car from cold listen carefully and you can hear the pump spin up. If you stop the engine at this point you hear it spin down again (like a turbo :)) If it's noisy when cold that could be a sign of trouble ahead, they have been known to fail I believe.

[Mooly]

This was one of several earlier threads... at the time no one knew what it was... and it all got a bit out of hand.

http://toyotaownersclub.com/forums/index.php?showtopic=10325&hl=89666-02090++89666-02091

As long as the pump is OK... which it probably is you have nothing to worry over.

[MrNadin]

This was one of several earlier threads... at the time no one knew what it was... and it all got a bit out of hand.

http://toyotaownersclub.com/forums/index.php?showtopic=10325&hl=89666-02090++89666-02091

As long as the pump is OK... which it probably is you have nothing to worry over.

so from what i grasp from that thread other than replace the ECU i'm stuck with it lol??

[Mooly]

Yes :) but it's not such a big problem surely. The new ECU would be programmed not to run the pump during driving.

The dimming is about the same as you get holding the window switches up, with the windows already up (which pulls the voltage down a similar amount).

Don't worry... it's just doing what it's supposed to, which is all in the interest of economy and emmisions.