lights dimming with heater on

[guest7224]

Hello,

I am hoping that you can help.  Just bought a honda jazz 58 reg, and whenever I run the climate control / air con / heater the main headlights dim.  They dim every 20 ish seconds for about a second.  The engine note increases slightly too when this happens.

Any suggestions to what is causing this, as I do not want to drive around with lights that keep flashing people.

Thanks
Aimee

[Jocko]

Welcome Aimee. I am sure someone will be able to help. Does the car start okay with the headlights on?

[guest7224]

Hello,

Thank you for the nice welcome.  Yes it starts ok.  Have had the battery and alternator checked, so not the normal culprits.  Everything else seems to work ok.

Thanks
Aimee

[Jocko]

Why I asked was a poor battery connection can lead to the lights dimming when an additional load is placed on the battery, and the surest way to find a poor battery connection is trying to start the car with the lights on. However, in your case that doesn't seem to be the issue. That is not to say there is not a poor connection elsewhere, such as the main fuse box.

[culzean]

Sounds like the lights are dimming when the aircon solenoid clutch is cutting in, it does draw a bit of power - that loads up the alternator and the aircon loads up the engine a bit so that accounts for the engine revs changing  as well.  If you run it without aircon / climate control on they should not dim.  Bear in mind that a 10% drop in voltage to a filament bulb results in at least a 20% drop in brightness, especially the brighter ones like headlights. 

As for garage checking the battery,  it is difficult to do,  as to do it properly they have to draw 100's of amps,  which most machines don't do.  If the battery is original it is well past its replace by date, can you see the brand of battery on the label ? If it is Halfords,  Bosch or some other makes it is not original - there is a date code on batteries and information on this site about how to read it.

https://clubjazz.org/forum/index.php?topic=9428.msg51223#msg51223

[JohnB47]

I've had my 2014 Jazz EX for just over a month now and I've slowly become aware of a slight dimming of lights and a slight lowering of engine revs with climate control (CC) or just air con on. When the engine is ticking over, this happens for around 5 seconds every 30 seconds. I can hear a fan kicking in for the 5 seconds and I've proved that it's the CC because, when the fan starts, I switch off the CC and the fan stops immediately. With CC back on, the fan starts straight away. (I thought it was the rad cooler fan at first).

When driving, I experience this as periods of slightly lower power for the 5 second period followed by an increase during the 30 seconds. It's feels like the brakes are being gently applied for 5 seconds and then released, with the car giving a slight surge.

I'm occasionally going up a gentle hill on 3rd or 4th, just enough power, then the power drops for a while, then you get the little surge. It is a tiny bit annoying.

I've looked at the battery, according to the manual and there's a little green (blue?) light glowing that's supposed to show that all is OK.

When driving with CC and Air Con off, I do not experience any of these effects.

Is this normal and just one of the downsides of Climate Control/Air Con?

[VicW]

With the aircon on the compressor does cut in and out at regular intervals as it manages the gas pressure.
However I am on my fifth Jazz, all with aircon, four CVT and one manual and have never noticed the slight surging you mention as the compressor cuts in and out.
I have noticed it on other cars I have owned or driven, some with larger engines than the Jazz and have always put the lack of surging on the Jazz down to a better engine management system.

Vic.

[Jocko]

A less than ideal connection, common to the air con clutch and the lights could cause a slight voltage drop which would cause the lights to dim, hence my enquiries regarding the battery connections. It would be worthwhile removing and cleaning up both battery connections, assuming you have the radio code!

[d2d4j]

Hi

Our jazz si has always dimmed as described.

Now I have the led lights, they no longer dim but I think it is because they do not use as much power

I have not noticed any surges, and the A/C is on all the time

Many thanks

John

[culzean]

Hi

Our jazz si has always dimmed as described.

Now I have the led lights, they no longer dim but I think it is because they do not use as much power

I have not noticed any surges, and the A/C is on all the time

Many thanks

John

The LED work on current not voltage and will tolerate from as low as 9 up to 30 volts DC supply

This dimming of filament bulbs will only happen at tickover and is nought to worry about.

[Jocko]

This dimming of filament bulbs will only happen at tickover and is nought to worry about.

From what I glean from the first post, Aimee's lights are not just dimming at tickover.

[guest7224]

Thanks ever so much.

I thought I had bought a rubbish car then!  I will check the connections etc just to be sure.  I like the idea of the LED's though, as I do not want to either cause accidents through flashing people (may have to rephrase that!) or the other option of having no heating and foggy windows for the next few months.

Are the LED's easy to get hold of, if so where etc...

The lights dim at tick over, and whilst driving too, otherwise I wouldn't bother fixing it

[culzean]

Thanks ever so much.

I thought I had bought a rubbish car then!  I will check the connections etc just to be sure.  I like the idea of the LED's though, as I do not want to either cause accidents through flashing people (may have to rephrase that!) or the other option of having no heating and foggy windows for the next few months.

Are the LED's easy to get hold of, if so where etc...

The lights dim at tick over, and whilst driving too, otherwise I wouldn't bother fixing it

I the lights are visibly dimming when you are driving you have really got a problem...are the headlights really dimming that much that people would think you are flashing them ?

read this thread about LED bulbs,  beware there are many cheapo LED H4 bulbs out there with proper illegal beams,  the ones from classicarleds.com are really good - I have them in my motorbike, wifes Jazz and my Civic - beam pattern is great.

https://clubjazz.org/forum/index.php?topic=8738.msg53034#msg53034

[guest7224]

Oh no, there was me thinking it was ok now.

May call the garage I bought it from then, as it is still in its one month warranty.

[JohnB47]

With the aircon on the compressor does cut in and out at regular intervals as it manages the gas pressure.
However I am on my fifth Jazz, all with aircon, four CVT and one manual and have never noticed the slight surging you mention as the compressor cuts in and out.
I have noticed it on other cars I have owned or driven, some with larger engines than the Jazz and have always put the lack of surging on the Jazz down to a better engine management system.

Vic.

Thanks.

I hope I'm not hijacking Aimees thread. I see she's getting lots of replies so prhaps not.

So, if I've bought a second hand car just over a month ago that's exhibiting these 'problems' what would you suggest I do. Is there a fault?

What do other Jazz 2014 EX owners experience?