Electrical problem.....

Post here if you require help or have information that may assist others with their MX-5.

Electrical problem.....

Postby Matt C » Fri Oct 16, 2015 6:03 pm

Hi there folks,

I wonder if anybody can help me with a wiring problem that is driving me round the bend!

I'm restoring a 1993 Eunos S-spec and have it stripped out, and have just finished replacing the control stalks (had faulty cancellation-cam) and replaced two blown bulbs in the instrument module.

On reassembly, I have lost all internal lighting in the instrument module, courtesy-lights, and external side lights. The rev-counter is dead, as is the oil-pressure gauge. Everything else is operational.

I have checked the connections, and all of the fuses that I can find. I have also removed an illumination-dimmer which I added, in case it was faulty.

Does anybody else have any ideas? Could the new control-stalk be faulty? Are there any relays which could cause this fault?

Very much appreciate any help!

Matt


Sent from my iPad using Tapatalk
Matt C
 
Posts: 34
Joined: Sun Mar 30, 2014 8:47 pm

Re: Electrical problem.....

Postby joeytalent » Fri Oct 16, 2015 6:16 pm

In the driver's foot well, I'd check the tail light fuse first - I'm fairly sure that is also the main fuse for the cluster. Then I'd check all the grounds under the dash and see if anything looks wrong..

Sent from my ASUS_Z00AD using Tapatalk
joeytalent
 
Posts: 424
Joined: Mon Jan 31, 2011 4:36 pm

Re: Electrical problem.....

Postby drumtochty » Fri Oct 16, 2015 6:42 pm

As Joey has said you have to trace wiring to find where the problem is and it appears that your work has caused the problem.

Therefore you have to go back to the start and find what you have disconnected and not reconnected.

There are three different wiring system used depending where your car was destined to be sold.

The Miata wiring system in the US.

Diagrams here.

http://www.mellens.net/mazda/

The UK car wiring digrams are available to purchase from Mazda but your car is not UK spec I think.

The Eunos wiring diagrams are availabe in Japanese and are different to the UK cars and to the Miatas.

Therefore you have a good bit of a detective job to do there.
99 Mk2 1.8 IS Silver
08 Mk3 2.0 RC Sport Copper Red
drumtochty
User avatar
OC Member
Eddie Cairns
MX-5 OC Club Member
 
Posts: 2601
Joined: Thu Jun 18, 2009 1:42 pm
Location: Drumtochty Glen, Auchenblae

Re: Electrical problem.....

Postby Matt C » Fri Oct 16, 2015 7:02 pm

Thanks for the replies, guys.

I guess that one of the problems of replacing components with other second-hand components, is that you don't know if you are replacing bad with bad....

My intention tomorrow is to replace the fuses, irrespective of whether they look sound or not. I've also put the battery on charge overnight, just in case it is also causing a problem. It's the only things I can think of. My connections are good, and the contacts cleaned with switch-cleaner prior to assembly.

Just wanted to check with you guys that this wasn't a common 'known' issue, before I spend a day fault-finding...

Regards,

Matt


Sent from my iPad using Tapatalk
Matt C
 
Posts: 34
Joined: Sun Mar 30, 2014 8:47 pm

Re: Electrical problem.....

Postby 71NotOut » Fri Oct 16, 2015 7:27 pm

I was losing my cluster/side/rear lights as well on my Eunos.

The fuse kept blowing, and replacing it only lasted a few minutes.

Tried removing the stereo to check wiring behind, looked at foglight switch/wiring, even removed sidelight bulbs (aftermarket) to see if they were the cause.

Ended up going to an auto electrician who solved the issue in 20 minutes.

One of the original wires in the wiring loom had chaffed over the years and was arcing out against a metal bracket holding a relay under the dash that had been bent up slightly allowing the 2 to touch.

He resealed the wire, bent the bracket back into position and voila - no more fuses blowing.

£50 well spent in my book (actually, to his credit, Steve Bloxham covered the cost as the car was still within it's 3 month warranty period!).
Previously in a 2003 Montana, now in a 1991 V-Special...
71NotOut
User avatar
OC Member
Steven Hedley
MX-5 OC Club Member
 
Posts: 412
Joined: Tue Apr 20, 2010 1:29 pm
Location: Bilston

Re: Electrical problem.....

Postby drumtochty » Fri Oct 16, 2015 8:19 pm

He had the knowledge!
99 Mk2 1.8 IS Silver
08 Mk3 2.0 RC Sport Copper Red
drumtochty
User avatar
OC Member
Eddie Cairns
MX-5 OC Club Member
 
Posts: 2601
Joined: Thu Jun 18, 2009 1:42 pm
Location: Drumtochty Glen, Auchenblae

Re: Electrical problem.....

Postby Matt C » Sat Oct 17, 2015 7:53 am

Thanks for that, mate!
I'll have another look today.

The biggest problem I have is that, other than a single 5 minute drive, I don't really know the car as I started stripping it down for a restoration the following day. I can't even use my 'daily' MX-5 for reference, as it is an NC model.

Good shout on the loom being disturbed or a bracket being bent. I did quite a lot of 'manipulation' at the back to get the speedo-cable to disengage after 23 years!


Sent from my iPad using Tapatalk
Matt C
 
Posts: 34
Joined: Sun Mar 30, 2014 8:47 pm

Re: Electrical problem.....

Postby Matt C » Sat Oct 17, 2015 8:37 am

One last query (on this circuit at least!)

I've sourced a dashboard illumination adjuster-switch from a donor UK model, and located a fitted dormant-plug off the existing loom to fit.

Is it just a case of 'plug and play', or do I need to populate the loom with a fuse somewhere, to make it live?


Sent from my iPad using Tapatalk
Matt C
 
Posts: 34
Joined: Sun Mar 30, 2014 8:47 pm

Re: Electrical problem.....

Postby drumtochty » Sat Oct 17, 2015 9:52 am

If it only has two connectiond then it does not need anything other than connected to the 12v supply to the dash lighting.
99 Mk2 1.8 IS Silver
08 Mk3 2.0 RC Sport Copper Red
drumtochty
User avatar
OC Member
Eddie Cairns
MX-5 OC Club Member
 
Posts: 2601
Joined: Thu Jun 18, 2009 1:42 pm
Location: Drumtochty Glen, Auchenblae

Re: Electrical problem.....

Postby Matt C » Sat Oct 17, 2015 7:05 pm

Well folks,

Today I swapped the mk1 hood for a mk2 hood (still to wire in HRW) , changed the gearbox gaiters and topped-up the turret oil (which was empty!)

Also swapped out the fuses in the driver-footwell fuse-board.

This has PARTIALLY fixed things with the electrical fault. My sidelights and dashboard-illumination are now working, but still no rev-counter or oil-pressure.

Oh well, tomorrow is another day....


Sent from my iPad using Tapatalk
Matt C
 
Posts: 34
Joined: Sun Mar 30, 2014 8:47 pm

Re: Electrical problem.....

Postby Matt C » Sun Oct 18, 2015 5:55 pm

Faulty instrument panel. £10 later and a visit to a local breaker, problem solved.


Sent from my iPad using Tapatalk
Matt C
 
Posts: 34
Joined: Sun Mar 30, 2014 8:47 pm


Return to Technical

Who is online

Users browsing this forum: No registered users and 2 guests

cron