Hi All
My 2011 NC has just decided it’s dash lights and hardtop controls should flash on & off randomly. This first happened just before Christmas after a similarly wet period and after spell in the garage it had cleared. Once again a wet spell has triggered it. It runs & drives ok but the speedo keeps dipping to zero but the Rev counter seems fine.
I figured some wet on the ecu connectors might do this but just had a look & it was dry & doesn’t look water stained.
Any suggestions gratefully received.
Ian
Have you checked under the dash by and in the small fuse box at the base of the A pillar passenger side? Reports of water ingress there causing electrical stuff to act as yours. Possible water entry by the grommets below the windscreen, many many members have found leaks there.
I agree with MickAP - it’s highly likely that the fault lies with failed scuttle grommets allowing water into the electrics.
This is quite an easy fix, suggest that you buy the two little black plastic covers as well as the grommets because the clips on the covers frequently snap off when the covers are removed.
Thanks, really appreciate the prompt response to my first post.
I’ve Just checked carpet there is wet, it didn’t seem particularly wet in the fuse box, but I guess it’d have to get by there.
Couple more questions;
Is it worth doing the grommets on both sides?
Looks like I might need to remove the bonnet to get the scuttle out?
Cheers
Rid
Pop the wiper arms off and the two black cover caps either side on that black plastic cover at the base of the windscreen. Behind the caps are two cross head screws, remove these. They are screwed into the failed grommets, the foam seals break down allowing water ingress. Anyway onto under the bonnet, you’ll see a long black rubber strip running the width of that black cover, this is held down through the cover and once released of the clips holding it the cover will be loose. The cover is in two pieces but no need to fully remove as it’s still held by the washer tubes. You can get to the two grommets easily.
You can buy two new seals or as most do just clean up and silicone seal around them and it’s sufficient. Take care removing the black cover caps, they break easily. And for good measure I silicone seal the screw hole before replacing the screws.
Great thanks for that, I just ordered the parts.
Should’ve seen it coming as I’ve been getting lots of condensation inside the car.
Rid
This is a common issue on the MK3 and crops up on a weekly basis.
If you’ve already ordered the grommets, then you might as well fit them.
However, the new ones will fail at the same point eventually (a few years).
I’d advise a smear of silicone sealant for good measure
As above but don’t even bother with the supplied foam gaskets.just remove the plastic grommets, bin the gasket, clean the seating area of the oblong hole in the scuttle and bed the insert on some non corrosive silicone type adhesive. Another thin layer around the edge once seated.allow to set before reassembly.
Thanks to All.
I’m just wondering if there’s an easy way to romove the old grommets…?
Is it a case of rip ‘em out?
Rid
I’ve not removed mine just sealed around them but I bet they are just held in by clips. I reckon if you get something like an old credit card or such a thin like blade under and push and lift it will release the clips.
See the image of the underside.
Hello all - could anybody please suggest a supplier for the black plastic caps? For some reason I’m missing one on my NC.
Thank you
Richard
Hi Richard, I got mine from MX-5 Parts. Somebody else recently said they’d bought some from a company called Autolink.
Thank you Mick - I’ve been struggling to find any (tbh, I didn’t know what to search for!) so I shall get some ordered.
Richard
Hi All
Thanks for the guidance.
I replaced the grommets, leaving out the foam pieces as suggested and bedded them onto a PU based sealant (Sika EBT) see pic. After a few more days letting it dry out in the garage, it was outside again for last weekend’s deluge and great news, it stayed dry & isn’t impersonating a Christmas tree anymore.
Thanks
image|666x500
I thought it would be okay to bump this thread rather than starting yet another scuttle grommet thread.
I purchased an NC at the end of November, 49k on the clock, perfect mechanically. Had a good look of the underneath and all the (or so I thought!) relevant points for rust, before purchasing.
Since owning, I have indeed been the culprit of the damned scuttle grommet leak. I had the headlight staying on scenario (OFF on the stalk), as well as the speedometer bouncing and ticking around the 120mph mark, all whilst no key was in the ignition. The PRHT latch light on the centre console was illuminated briefly before going out, too.
I’ve taken the glovebox out and discovered a rather large and possibly concerning amount of rust on one of of the metal frames, directly above the fusebox.
The car was bought from a dealer down in England (I am based in Scotland), and although I’m led to believe I’m within my rights to ask for a repair or replacement as it’s quite clear that the water ingress has been happening well before my ownership of the car due to the significance and amount of rust on the metal, I would rather just tend to the issue myself and make sure it is done correctly, as the time and inconvenience involved would be rather costly, as well as the never ending anxiety of being fobbed off by high street dealers.
My question would be, other than making sure the grommets are sealed up good and proper, and making sure that the fusebox and behind is dry - would there be anything else to watch out for after these electrical gremlins have already occurred? Or is it a case of once everything has dried out and there’s no corrosion in the box or wiring itself, it should be okay?
All dried out in the fuse box area and grommets sealed it should be ok electrical wise.
Is it ok now?
As for the rust, I’ve seen this on past NC’s owned, not as bad as on yours. Get it cleaned off with a wire brush or better a Dremel type tool and the some rust treatment and paint over. It’ll be difficult to get at but at least arrest the corrosion getting any worse.
The area seems to be bone dry, but I haven’t managed to get a chance to get into the grommets.
The battery is flat at the moment, and I was pretty set on making sure the area was bone dry before attempting anything else at all.
Might I add - I’m at a friends house when it all happened and they had a (very) limited tool kit, so I would have found it difficult to even disconnect the negative terminal from the battery to try and “reset” the speedo. Next idea is to raid her make up bag and see if she has any tweezers to remove the fuse.
Passenger grommet changed and after last nights rainfall seems to have held up successfully!
Lifted the mat and the carpet was dry underneath all the way back, so that’s good news too.
We’ve managed to take apart the fusebox and relative connections, and noticed that there are what seems to be 3 pins corroded into the block. Everything else seems good (apart from the superficial oxidisation).
Managed to get the battery jump started but the engine would not turn over, at all.
I would imagine that these pins are the problem, but how much of a pain in the ■■■■ is it going to be to replace? Would it be a case of just cutting out the old wires and replace?
There seems to be next to nothing online regarding diagrams/info regarding that fusebox, only the engine bay, so I’m a little lost.