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        General >> Off Topic Subjects >> Mondeo speedo problem
        
(Message started by: Jonnycab on Aug 12^th, 2010, 4:14am)

Title: Mondeo speedo problem
Post by Jonnycab on Aug 12^th, 2010, 4:14am

Just wondered if there were any MK3 Mondeo techie/knowledgeable folk here ?....as a mate of mine (fellow cabbie) has a 53 reg 2.0 diesel Auto Mondeo with a speedo problem.

Intermittently the speedo will stop working & the digital odometer will read just lines where the digits should be....& at the same time the taxi meter will stop clocking up the fare (good for the punter eh ;) )

His local mechanic that he has used for a few years & so trusts him, has diagnosed a bad 'speedo head' & quoted a bill of £400 for a new dash from Ford :o....plus £30 labour to fit.

But I'm not convinced the mechanic's diagnosis is correct & have told my mate that it sounds more like a VSS problem, mainly due to the fact that the taxi meter is spliced into & takes a pulse from a wire at the back of the radio (like most taxi meters are)....hence a bad dash shouldn't affect the running of the meter.....or would it ?.....does this pulse wire run from the dash ? :-/

Any thoughts or theories ? :)

Title: Re: Mondeo speedo problem
Post by Simmo on Aug 12^th, 2010, 5:33am

Jon, I put 'Mondeo Speedo Problem' into Google and there are numerous links...BUT...there seems to be a common thread about the VSS which apparently is hard to find but either on top of or on the side of the gearbox. There is also a mention of the fuel warning light coming on at the same time?. HTH

Title: Re: Mondeo speedo problem
Post by Tompion on Aug 12^th, 2010, 11:13am

Could be the other way round - when the taxi meter stops clocking up the fare the speedo stops working. It might be worth re-making the meter splices or disconnecting it from the radio wire.

Title: Re: Mondeo speedo problem
Post by Jonnycab on Aug 13^th, 2010, 1:31am

Mike, I read the same when googling it, although VSS problems seemed to be more common in the MK2 Mondeo. Also read about the fuel warning light coming on when it's a problem with the dash (dry solder joints etc), but my friend doesn't have this :).....have also read that a VSS problem can turn on the 'Check Engine Light', but he doesn't have this either :-/
I did plug my handheld scanner in & it came up with 'no codes'. But this is no surprise, as it tends to only display engine fault codes ;)

Dave, good thought....I'll ask him if the speedo drops when the meter isn't on....although I'm not sure that this could be a cause :)

I've never fitted a taxi meter before, but as far as I know the wire behind the radio that the meter takes it's pulse from is the wire that comes from the VSS & provides the radio with speed sensitive volume.....I just need to find out if this signal comes from the dash or it is split before it reaches the dash :)

Title: Re: Mondeo speedo problem
Post by tlundkvi on Aug 13^th, 2010, 10:13am

My VSS's bearings gave up at 178000km, and I believe the mondeo VSS has similar construction. It worked when engine was cool, stopped working once it got hot. I think the gearbox has another set of codes read a special way as e.g. ABS codes, I recall getting no codes either.

Title: Re: Mondeo speedo problem
Post by Highlander on Aug 13^th, 2010, 2:35pm

"Intermittently the speedo will stop working & the digital odometer will read just lines where the digits should be....& at the same time the taxi meter will stop clocking up the far"

No experience of Mondeos but using Scorpio logic I would doubt a dodgy VSS would do that to the odometer...

As you say the speedo reading shouldnt stop the meter so... must be the wiring! EASY ;D

Title: Re: Mondeo speedo problem
Post by Mike H on Aug 13^th, 2010, 3:24pm

on 08/13/10 at 14:35:36, Highlander wrote:

but using Scorpio logic I would doubt a dodgy VSS would do that to the odometer...

I thought that actually

Title: Re: Mondeo speedo problem
Post by Jonnycab on Aug 15^th, 2010, 2:12am

Well......my friend didn't take my advice to get a second opinion from an auto electrician & went ahead & had the garage put a new dash in on Friday :-/

Total price came to over £500 inc VAT.....& what happened when he got half a mile up the road ?....yep, you guessed it, the speedo stopped working, the odometer just read lines & the meter stopped totting up.....so nothing's changed apart from his bank balance.....some people never listen ::)

It's now back in the garage again for the weekend while they try to figure out what is really wrong with it.

......ooh, the suspense is killing me ;)

Title: Re: Mondeo speedo problem
Post by Jonnycab on Aug 15^th, 2010, 2:32am

Heads up !! ;) ....just found THIS (http://www.fordmondeo.org/forum/showtopic.php?tid/785491/)

Exact same problem on a 52reg TD Mondeo & if you read the second from last post, it says it was diagnosed as a faulty VSS :)

Title: Re: Mondeo speedo problem
Post by Jonnycab on Aug 21^st, 2010, 3:13am

Problem solved.....the original garage gave up on trying to fix it & told my friend to take it to Ford.

So he booked it in at the local FMD, where they diagnosed it as a faulty VSS. So in goes a new VSS & what do you know ?....it didn't solve the problem ::)

After much head scratching, FMD stuck a new battery in it & voila!!!....the fault was cured :o

Now, what confuses me ???, is that there was no evidence of a battery fault when starting the car & the fault would only occur while the vehicle was in motion. There was no battery/alternator light illuminated, not even faintly & no DTCs were detected when plugging in my handheld scanner.

Seems that maybe applying Scorpio logic to the MK3 Mondeo doesn't work......or maybe (more likely) FMD are fibbing & it was actually just a loose earth wire & they just fancied selling him a new battery just to bump up the cost ? ;)

P.S...my friend is currently trying to get his money back from the original garage & has so far got the cost of the new dash back, but they are refusing to reimburse him on any labour costs ::)