Electrics tripping out when driving

[Mariusz]

Hi, I've got a Renault Clio 182 2004, with 77k miles and today the electrics started tripping out whilst driving to work. The radio, fans and lights would go off then come back on again after approx. 10 seconds. The dash would light up like a Christmas tree. I noticed tonight when I went to pick a takeaway up that when slowing down, that after braking for a few seconds the battery warning light would be lit. I'd stop at junction etc, then pull away and light would go out. The car has been serviced recently, new oil, filters, spark plugs, ht cables and coil pack, all oem. The battery is less than 6 months old. Is it my alternator? How do I check?

 

[da rok]

sounds like a lose earth strap or lose connection on the uch, can test the altinator by testing what voltage its putting out while running, should be 14 volts, other than that, give all the earth straps, relays, plugs a clean...

 

[Mariusz]

Bought a multi-meter and checked battery, it was reading 12.8 volts, then when I started car it went up to 14 volts. So don't think it's my alternator. Drove through to girlfriend's, around 16 mile away with radio, lights & climate control off and the dash lit up like a Christmas tree a few times but went off straight away. Checked the fuses in the bonnet and glove box and everything was seated correctly.

 

[da rok]

check the earth straps, there are 4 of them in the engine bay, one from the battery to the pannel work, one to the gbox, one to the starter, and one by the brake fluid reservoir

 

[Vaughan]

I just bought a 172 whose previous owner just drove the poor thing and never serviced it. Got it cheap though. It ran rough even after changing plugs. While washing the engine down I noticed that little bubbles were being made between the ECU box and positive battery terminal (the red cover was missing). Turns out there was less than 1mm clearance between the metal cover and the live terminal. The ECU had wear marks in the paint too. As the engine moved around under load the terminal would short on the ecu and drop voltage enough to cause the rough running.

So check that too.

 

[Oggy997]

I'd definitely check the earth from the gearbox to the chassis, visible behind the passenger side front wheel.

Very common to corrode and fray

 

[Mariusz]

Weather was terrible yesterday so didn't get a chance to look at car, come out today to try to solve my issue and car won't even start :confounded::weary::triumph:

 

[Mariusz]

Just tried the following ;

1. Turn ignition on to the second click and leave the car door open so you don't get locked out.
2. Disconnect the battery. (8mm spanner on negative terminal)
3. Wait for 2 or 3 mins.
4. Re-Connect battery.
5. Turn the key off and remove.
6. Get out, shut the door and lock the car.
7. Un-lock the car and try to start it.

Thanks for the tip @lewisflintham but no joy.
If I leave car for a bit it tries to start but just doesn't quite make it.

 

[Mariusz]

So went out to car again and I've noticed when I try to start the car the clock on the top display goes out. Also got the following lights on;

The rad immobiliser light is solid. Only got one key, so can't try a spare.

 

[Mariusz]

OK an update, managed to get the car started, was a loose relay in bonnet when I'd been investigating the electrics.

Still got an issue with electrics tripping out when driving, found if I drive like Vin Diesel they trip out but if I drive like Miss Daisy they are OK. I've checked and cleaned the battery negative, the ones behind headlights and gearbox to chassis strap, but still no joy. Also when my dipped beam lights are on the symbol for main beam lights are on aswell, flick stalk and it takes the symbol off dash for dipped not main lights :nomouth: (but my main beam lights don't work at all).

 

[Rone]

Sounds like a bad decoupling capacitor, or a main filtering capacitor, or a dry joint on the UCH PCB.
Next time you encounter the christmas tree symptom try to wiggle the black 40-pin connector around the slightest bit - located on the UCH. If this seems to have an effect then I would suspect a failed solder joint on the UCH PCB itself.