Strange fault MONDEO ST200

corktina

AT times last night (enroute to Dublin airport over 5 1/2 hours driving) there seemed to be a "pulse" in the dip beam, slightly dimming and brightening at about the frequency of the indicator flash, but with nothing running. (Turned off the a/c and climate control)

Any ideas what this may be? It was very random, my guess is something cutting in and out, but what?

ArnieSilvia

Been chasing something similiar. Usually flickering lights means alternator on it's way out. That's what symptoms were on my alfa 147.

In any case check first what bulbs you've got in there, if 120W ones, ditch straight away. Then check all connections at lights and clean grounds to chassis. Then battery voltage must be over 12V with engine off, about 13.8-14.2 with engine running (might be a bit less with all accessories on).

Would be worthwile to check condition of battery while you're at it, turn lights on with multimeter at battery and see if voltage is dropping fast. Check another battery in same scenario in case there's broken wiring (chafing/water damage).

mondeoman2

corktina wrote: »

AT times last night (enroute to Dublin airport over 5 1/2 hours driving) there seemed to be a "pulse" in the dip beam, slightly dimming and brightening at about the frequency of the indicator flash, but with nothing running. (Turned off the a/c and climate control)

Any ideas what this may be? It was very random, my guess is something cutting in and out, but what?

Did you notice a pulse with the revs also?

corktina

no , constant speed cruising but very random came and went, I wondered if the radiator sensor might be duff and cutting the fan in and out (temperature was rock solid....

(I did notice Climate Control panel was hot-ish to the touch but it might have always been hot)

corktina

ArnieSilvia wrote: »

Been chasing something similiar. Usually flickering lights means alternator on it's way out. That's what symptoms were on my alfa 147.

In any case check first what bulbs you've got in there, if 120W ones, ditch straight away. Then check all connections at lights and clean grounds to chassis. Then battery voltage must be over 12V with engine off, about 13.8-14.2 with engine running (might be a bit less with all accessories on).

Would be worthwile to check condition of battery while you're at it, turn lights on with multimeter at battery and see if voltage is dropping fast. Check another battery in same scenario in case there's broken wiring (chafing/water damage).

lights weren't flickering, they were pulseing (bright/dim/bright /dim but only fractionally)

mondeoman2

corktina wrote: »

lights weren't flickering, they were pulseing (bright/dim/bright /dim but only fractionally)

Have You Replaced the Alternator recently?
If you use a non Ford alternator on these the lights pulse, but so do the revs(like its going to cut out)

corktina

no but car not done many miles with me and maybe previous owner replaced it.... no problem with revs though...perfectly normal other than the pulse

islanderre

I have a 01 Honda Civic for the last 5 years or so....... same battery and same alternator and my lights have always done as you describe if I lift of the gas at a corner and immediately go back on or when slowing down @ traffic lights / roundabouts.

It has never been an major issue or concern but I've always wondered about it. All I could think of is could it be the alternator powering the lights when the engine is on load and the battery comes into play when foot off the accelerator??????? like an electronic change over switch of some sort.

Maybe Nissan Doctor could commen; although unfortunately have not seem him about here in a long while.

corktina

mine doesn't do that..it was when cruising on the mootorway

grainnewhale

I would be leaning towards altenator. out of interest would there be much poke in this as I have st24, while its nice to drive its no rocket.

L-M

You can get the alternator checked, which I would recommend. Nothing worse than getting caught with a knackered alternator.

corktina

grainnewhale wrote: »

I would be leaning towards altenator. out of interest would there be much poke in this as I have st24, while its nice to drive its no rocket.

I'd say the ST200 is a good bit faster....she is a flyer, although the ST170 is not far behind.

WIll check out alternator before it goes back on road, hope it isn't that because my mechanic had trouble trying to get it out before (failed to do it but found a broken wire eventually, maybe this is linked?)