Common Electrical Failure Points

[AlanWak]

Just going through sorting the issues with my "new" 172. To date I've hit the following electrical problems:
- door open light on all the time, all sensors seem fine, nothing on CLIP,
- a week ago, the starter wouldn't turn over intermittently, but started in the end. I'm tempting fate, but that problem seems to have gone away,
- two days ago the SERV and Airbag light came on for a few miles. Stopped and restarted, lights went off, drove a few miles, back on again. Varying distances before the light comes on, but it's happening more often so something is getting worse. Not connected to CLIP yet for this problem. No driver airbag as after market steering wheel. Resistors were fitted by the previous owner and lights haven't come on before in my month of ownership.

I don't know whether these are related or independent failures. I've had various electrical problems with my Rover rally cars, most of which came down to breaks in the wiring which flexes going in to the tailgate. After CLIP, I'm not sure what to do next to disgnose what's wrong with the Clio. Is there a known weak area in the loom for a 172? Any thoughts appreciated as the car is (now) coming together mechanically, but the electrics are driving me nuts - I'm losing confidence in the car, especially as the Autosolo season has started and I need the car to be 100% reliable.

 

[McGherkin]

1. Boot sensor maybe?
2. Did the immobiliser light on the dash flash rapidly when trying to turn the engine over? Also check the engine earthing points.
3. Airbag light will probably be a dodgy connection with the resistor, the airbags and pretensioners can be disabled individually through CLiP which should solve that issue.

 

[AlanWak]

1. Boot sensor checked out ok. Has to be a break somewhere else.
2. Didn't notice, I'll watch the lights if it happens again. I could hear a relay click under the dash, just as when the car does start properly.
3. Has to be, I'll have a wiggle, but a basic question - I've searched but can't find it - where would the resistors be fitted? Will have to find somebody with CLiP nearby.

 

[McGherkin]

Resistors under the seats to replace the dodgy pretensioner connectors, you said some had been fitted already?

 

[AlanWak]

I'm assuming so as the airbag light wasn't coming on and it has an aftermarket wheel with no airbag. I've read the resistors can be soldered in or plugged in. I'm not sure what to look for, I'll take a look under the seat right now and retrieve half a bottle of red (which slipped under the seat after the airbag light started playing up).

 

[adamlstr]

- a week ago, the starter wouldn't turn over intermittently, but started in the end. I'm tempting fate, but that problem seems to have gone away,

A buggered battery will do this. Especially when it's cold.

Airbag and SERV light can be the connector under the passenger seat.

 

[AlanWak]

The battery should have been fine - I'd just driven 150 miles and had stopped for fuel. Having said that, I have had a battery fail internally on a rally, sometimes it worked, others nothing. I'm carrying my jump starter, if the car fails to start again I'll throw it on and if it works then battery seems likely.

I thought I had the air bag light cracked - connection under the driver's seat wasn't fully home. Only a very small movement to push the connection fully closed, lights stayed off at first but came on again after a few miles and has stayed on. I'll have a look under the passenger seat tomorrow between tests on the Knutsford Autosolo. I'm assuming that the passenger air bag is still present, so would anybody have inserted a resistor below the passenger seat or just the driver's seat as the steering wheel air bag has been removed?

 

[McGherkin]

Are you sure the resistor that's been fitted isn't to replace the steering wheel airbag?

The underseat connectors are notoriously dodgy, so it may be worth either soldering them up directly or fitting a resistor.

 

[AlanWak]

That's what I'm assuming - whatever has been done to the wiring has been to cater for the removed steering wheel air bag. I haven't checked to see if the passenger air bag is still there but there's not an air bag on the driver's side. Does the passenger side need the resistor soldering in as well even if only the driver's air bag has been removed?

Attached a picture of what I've found under the seat. the bundle of wires with what looks like masking tape around it goes down under the carpet. There's insulating tape wrapped around the lower part of the cable bundle so I'm guessing that's where the resistor has been fitted. I'll pull it all apart and check the connections in the plugs next week when I have more time.

 

[McGherkin]

That doesn't look like it's been touched.

 

[adamlstr]

If you've still got your airbag ECU in the car, get someone with a diagnostic tool (Clip / Autologic etc) to delete the airbag via software.

Much better than dicking about with resistors IMO.

 

[AlanWak]

Those connections were under the driver's seat, I haven't looked under the passenger seat as yet.
But more fundamental problems anyway - I'm typing this in Demon Tweeks after the power steering pump failed and blew oil everywhere. I'm assuming the pump as the pulley looks to be wobbling from side to side, but it could be a hose. Now to arrange recovery. To add insult to injury, the OS handbrake cable also snapped.
On the stsrting front, the car started fine this morning. 168 miles to Demon Tweeks, went to restart and just click, no starter spinning. I fitted the jump battery and no improvement - probably not the battery. I checked positive and negative connections, plus earths, no change. However a wiggle of the ECU cable /junction and the car started. I'll focus on that area.
I must admit that I'm very disillusioned with the Clio, it's costing the earth and I can't depend on it. Do I keep on throwing money on it? . When it goes, it's fantastic, but right now it's very unreliable. My 100% reliable Micra is at hom, slow, but competitive in class. I'll have to sleep on it.

 

[McGherkin]

A PAS failure like that isn't a common thing, so I don't think you'll get it again. Likewise with ECU wiring, if it is that.

 

[AlanWak]

Back home now. A good sleep in the recovery truck, I did have a 4am start after all.
Could this happen again? When I acquired the car the PS reservoir cap had fluid on the outside and the level was low. I topped it up, cleaned the outside of the cap but there was still PS fluid appearing on the cap a few days later. I guess there's a breather in the cap and some fluid was being pushed out.
I'm wondering if it's possible to over pressurise the PS system? I felt (but didn't hear) a "pop" then the steering got heavier as it lost fluid. I'd just finished a tight test on the Autosolo and started the next test after a short (one minute) break. I have boiled/aerated PS fluid in other cars in the past. I wonder if I'd done the same, but the pressure has blown something. Inevitably I'm concerned that it might happen again. Is there a pressure valve somewhere in the system which could be stuck?

 

[AlanWak]

Found the starting problem, a simple thing - exciter wire had been touching the exhaust manifold, melted through and was shorting out.

 

[AlanWak]

And the SERV/Airbag warning light was due to the connection under the passenger seat, as you all said, thanks.

Now to discover why the door open warning light is on all the time, but I haven't a clue where to start. Thoughts appreciated.

 

[Rubicon_]

I was getting the door open warning light, it was due to water getting in through my polycarb Windows and dripping inside the door.

 

[AlanWak]

It looks like I'm going to have to go through every connection, it will probably be really easy to fix when I find the problem. Any indication of where to start appreciated. I was hoping that there would be a common problem area, such as the wiring under the passenger seat for the air bag light. All the door and tailgate switches have been tested. It's probably a connector coming apart or a bad earth as the problem was initially intermittent, but now the light's on all the time. Nothing in Clip.