Rekusu

Hi there, First post here, so you can really shoot me down! I have a Mondeo Mk3, and the dipped lights have both given up the ghost. I have checked everything and there does not appear to be any problems. All the other lights work as they should. Fuses all checked, continuity OK and swapped the relevant ones. Checked the engine bay relay and swapped it with the starter relay; both start the car and they both click, so guess they are OK. Likewise with the glove box relays and fuses. Checked the actual bulbs and they are both OK. Exchanged the light switch and that did not bring the dipped lights to life. Cleaned the engine bay earth points and still nothing. Dismantled and cleaned the main beam switch, but still no dipped beams. Have used the GEM to check but that only tells me that the side lights are working, which they are. So what is next? Really grateful for any suggestions and/or advice. Apart from anything else, this is an MOT failure. Many thanks, Rekusu

RichieST

iTrader: (2)

Did you also check the fuse behind the glovebox as there is one there that gives power to both headlights.

bluescortcossie

relay holder corroded ?

ive had to fix a few mk3 mondeos with electrical faults , both to the wipers , 1 was a corroded relay (which when put on the horn circuit worked fine but not on the low load wipers circuit) and the other was a corroded connecter on the relay

both were in the box under the bonnet , not sure if the lights relay is in there or in the cabin without looking

check for power and earth at the relay connectors and also try another relay from another circuit

Rekusu

Gentlemen, Thanks for the replies. Yes, I have checked the fuse and relay behind the glovebox and both OK. I have been thinking of a corroded relay. The starter and dipped beam are the same, and I have already swapped them. The dipped beam started the car so I figure it is working but the starter relay did not bring the dips to life. Have also given all plugs and sockets (relays, light units) a shot of WD40 in the hope that will clean them. Wiggled all wires at the plug and socket ends, but zilch. Also opened up the dip beam relay, gave is a clean and a shot of WD40. Looked OK on the inside and probably did not need a clean, but still no working dips. I have wondered about a corroded contact under the fuse box and spent half the afternoon trying to remove the fuse box but gave up. Any ideas on how to remove it. One bolt at the back, one nut inside and remove the red and green plugs, but then what. Seems that the fuse housing is a two piece molding, but how to separate and remove them? Rekusu

dojj

iTrader: (3)

there are 2 fuses in the engine fuse box as well

Rekusu

I know. Been there, done that. And when I check them all a second time, surprisingly, they are as they were the first time. Have done everything and more that Hayes suggests, but still no dips. Whatever the problem, it is obviously common to both lights. If I get an auto electrician involved (not out of the question) it will cost a small fortune to find a Ł3 replacement part. What else can I check? How do I test a relay for volts and continuity? I only know how to use a meter in the simplest way. Rex

dojj

iTrader: (3)

you won't get the fusebox apart in the engine bay without removing the battery tray and virtually everything else around it,including the wing and the front plastic cross member so don't bother

the simplest way is to find the feed to the dipped beam and see if the earth return works

i had a problem with my lights as the return earth inside the light has overheated and wasn't giving enough whatever to get the signal to ground out so i simply added another earth wire to the loom and hey presto it worked

easiest way to do it though is to find out if there is power all the way through from the fuses to the switch to all the plugs etc

Rekusu

Doji, Thanks for your reply. Will take your advice and not use a crow bar to the assist in the fuse box removal. As for 'finding the feed to the dipped beam and see if the earth works.' Sounds easy but in practice, I have no idea how to go about this. Was playing around with the continuity meter this afternoon and seem to get continuity from everything, which only points to the fact that I don't know what I'm doing! Rex PS Trivial and off topic, but although I post with paragraphs, the post on screen appears with no formatting. How do I correct this?