Not another brake light problem

pj110

Guest
Hey all, apologies if this goes over old ground. Have looked at many posts about flashing glow plug light and brake lights but having tried several things to resolve my issue I am now at a bit of a loss.

First glow plug light started flashing, checked all lights and everything worked fine. Had a play with the brake light switch and now the brake lights are stuck on. Guessing I had broken it i have bought a new one but as soon as I plugged it in brake lights came on and won't go out. Has anyone got any ideas please?
 

Blanco92

www.racedriversinc.com
Apr 11, 2010
2,496
4
Bournemouth/Cheshire
Not trying to tell you how to suck eggs mate, but are you sure you've fitted it properly? Lots of people replace these, then replace again because they think the switch is faulty, when actually they've just fitted it incorrectly...

Contrary to what I've heard on other forums, I found the brake switch needs to be fitted WITHOUT the brake pedal depressed, and once it's in position, it needs to be rotated about 90 degrees until you hear it click. Is this what you've done?
 

pj110

Guest
Hey, thanks for the reply. I have now resolved brake lights staying on, turns out I need lessons in sucking eggs! Anyway embarrassment out of the way, I am now back to my original problem - glow plug light flashing. I can now rule out switch and bulbs so would this lead me to new glow plugs as the only option left? Or are there possible other causes meaning I should take to a garage for diagnosis (unless anyone has vagcom in the Canterbury area :)). Any advice gratefully received.
 

DavieTDI

Brain dead
Aug 3, 2013
332
28
kilmarnock Scotland
plug it in and see what comes up. or you can just start replacing everything that would cause the light come until you find the fault. vagcom would be the easy option
 

Blanco92

www.racedriversinc.com
Apr 11, 2010
2,496
4
Bournemouth/Cheshire
There may not be any further problems!

Try a fault code reset. It's not unheard of for the brake light switch fault to require a reset before allowing the warning light to go off.

I would offer to do it but I'm quite a distance from you.
 

pj110

Guest
Thanks for the help, much appreciated. Will take to a garage to checkout. I'll post the outcome for future reference. Cheers
 

pj110

Guest
Thanks spud, would you be willing to hook me up for some beer tokens? I work in ashford
 

pj110

Guest
So thought I would put in a bit of an update on this problem with glow plug light flashing. A couple of days after changing the brake light switch the glow plug light stopped flashing only to return another couple of days later. Took to the garage and they cleared the fault code and all appears to be well now so will just have to run and fingers crossed no more problems. The garage recommended fitting a genuine part if the problem comes back as I got mine from euro car parts.

Unfortunately three more fault codes have been picked up - fuel temperature sensor, (already knew about, I replaced a while ago but fault won't clear), camshaft and crankshaft sensors. These probably explain starting issues I have been having. Does anyone know if there is a second fuel temp sensor on Ibiza FR tdi mk4? Are the cam and crankshaft sensors reasonably easy to do?
 

Blanco92

www.racedriversinc.com
Apr 11, 2010
2,496
4
Bournemouth/Cheshire
I agree with the advice you got there, when it comes to these brake light switches, fuel temp and coolant temp sensors etc, I'd only fit genuine ones. The last brake light switch I fitted only cost £12 from the dealer. Particularly the brake light switches have been superseded a few times over the years.

Are the fuel temp, crank and cam fault codes all recurring ones?

I'm not sure about the TDI but the crank sensor on my 1.2 was a pig to get at.
 

pj110

Guest
Fuel temp and camshaft sensor codes are! Not sure bout crankshaft one, the garage said it wouldn't clear but it didn't appear when AA hooked car up. Had to call them out as car wouldn't restart when I had just stopped at a shop, was only in there for 5 mins. Car started fine with a battery booster. The guy plugged the car into his fault code reader and showed fuel temp and camshaft sensor faults and he couldn't clear them. Do you know how I can test if its the actual cam sensor or faulty wiring before I buy a new part? I also experienced a sudden loss of power on way home, car just started slowing almost to a crawl, was almost home and road clear so took it out of gear and coasted for bit and almost as suddenly as it lost power the car just seemed to sort itself out.
 

pj110

Guest
Thanks for the advice, couldn't see any obvious breaks in the wires near the plugs and it started raining quite heavily so couldn't trace any further back, not even sure I could anyway. Looks like a big job just to follow wires back to find a break!

Not sure if I was doing this right but did try and use a voltmeter in the plugs to get some readings, if any one is able to make some sense of the readings it may confirm the wiring problem. I believe the black plug above grey one is cam, grey one is crank and the other is fuel, readings with ignition on:

Cam - Pin 1 - 12.32 Pin 2 - 0.48 Pin 3 - 0.00
Crank - Pin 1 - 2.35 Pin 2 - 2.34 Pin 3 - 2.34
Fuel - Pin 1 - 0 Pin 2 - 0.31

Apologies if this is all a bit amateurish!
 

spud31

Rail Zip User
Jul 14, 2011
404
1
Looks like crank and fuel temp are shorted together in the loom.
Cam looks ok 12v supply, signal, and earth in that order.
will look up the wiring colours to help later.
 

pj110

Guest
Thanks mate, I guess that would narrow it down to the camshaft sensor then. I'll have to see if can find any issues with the wires for fuel temp and crank sensors. Think I know where they go to now, just gotta try and get to them to have a good look.
 

pj110

Guest
Thought a sit rep is in order! Turns out you were correct spud so thanks for your help on that one as having inspected the wires I found some breaks and points in the wires where little holes in the plastic coating are appearing. I have repaired as best I could, in an ideal world I would have replaced the wires lock, stock and barrel but could not source the correct gauge wire anywhere.

Took my car back to the garage to plug it in and clear faults for me. Big thanks to The Motorist Centre in Hersden btw, if anyone in the Canterbury area is looking for a good garage I really recommend them and they specialise in Seats. They did it for free, it was only 5 mins of their time but much appreciated.

Anyway I seem to fixed the fuel temp sensor fault and I no longer have an illuminated engine management light but still getting camshaft sensor fault. It seems the crankshaft fault was a bit of red herring as that did not show up and I haven't done anything with the sensor or its wires. The garage said sometimes a camshaft sensor fault can throw up a fault with the crankshaft one erroneously.

I can only assume I haven't fixed all the breaks in the wires which is certainly possible or the connections I made are not good enough. It is also a new camshaft sensor and a genuine part so unlikely to be that but not 100% ruling it out! Struggling to find what readings I should get from the wiring the sensor plugs into, I get 12v from pin 1, 5v now from pin 2 and 0v from pin 3. If anyone knows I would be grateful, as frustrating as this problem is I will not let it beat me!
 

spud31

Rail Zip User
Jul 14, 2011
404
1
Cool thought i would be lol, usuallly get damaged when clutch changed.
I would look and see if engine timing is right now as readings from plug seem spot on.
Has it had a recent cambelt ?
Using vcds would show due to kw angle being miles out.
i have also heard of people using wrong cambelt pully if theve damaged it so the cam sensor pickup is wrong one
 
Last edited:

pj110

Guest
Campbelt was 10k ago, the timing was checked by garage when fault first found and they said it was fine. I think I had the difficult starting before the cambelt anyway but it has got progressively worse. Trying to source a new loom from a breakers at the moment as my gut feeling is I still have a wiring issue somewhere.