Follow up thread - car permanently live

[NWTony]

Having broken into my own car it turns out it wasn't the alarm, the battery was completely flat as a pancake. I've got a friendly garage to jump start me this morning but when I pulled up and switched off the dash was still on, which at least explains the flat battery.

I've disconnected the main fuse to save the battery (locking myself out of the car again - doh!)but any suggestions as to what would cause this?

Arghhhh TVR electrics!!!

All help gratefully received

[LeeT350c]

Alternator diode pack has failed.

Cheers

Lee

[shep1001]

replied to your mail but as Lee has suggested the symptom you describe still points to the alternator being the culprit.

Andrew

[NWTony]

Charge seems OK, 13.5 ish when driving along?

Is the permanent live a well known symptom of Alternator failure? This alternator was repaired within the last 6-12 months, it failed last time but it was obvious from the dash read out.

[twinreal]

If the alternator still charges correctly (With ignition on the reading should be around ~12,5 V and with engine on it should be higher, at around ~13,5 V), then maybe the D+ Diode should do it without swapping the alternator.
See this thread: http://www.pistonheads.com/gassing/topic.asp?t=129... and suggestions of LeeT350

[Cerberus90]

When the dash got stuck on on my dads T350, it was the dash and dash ecu stuff that had gone duff, had to be sent of for repair and was apparently pretty melted and knackered (somehow), all fine now.

[EvoOlli]

Easiest way to find out is to remove the D+ cable from the alternator. If the Dash shuts down after that: Voilá, you need the extra diode.

Replaced the alternator on my Sagaris last winter, car was fine without the extra diode. 6 weeks ago Dash didn't shut down, but did with removed D+ cable. So put in the Diode as described: No problems since then. Why it worked first time I don't know.

[NWTony]

Thanks to Shep and everyone who replied, it does seem like it is the alternator with the symptoms and the info from the other thread.

Do we think new alternator or just a diode?

I'm not aware of a diode being in line with the current alternator and it has worked fine (up until now, obviously, now it's crap!).

Thanks again.

[shep1001]

NWTony said:

Thanks to Shep and everyone who replied, it does seem like it is the alternator with the symptoms and the info from the other thread.

Do we think new alternator or just a diode?

I'm not aware of a diode being in line with the current alternator and it has worked fine (up until now, obviously, now it's crap!).

Thanks again.

a 'propper' tvr alternator, pinched from the disco's part bin I think, had all the necessary gubbins inside it to ensure it was compatible with the TVR set up. Some aftermarket units require an additional diode from somewhere like Maplins that cost about £1. (Lee had a thread about this and how to install it). Refurb maybe an option but I am not sure. If you go for new don't bin the old one first as you may need the pulley off the end as its different (number of belt grooves) to the TVR. Good luck getting it off it can be a bit of a sod.

[Session]

My car did this whilst in france a couple of years back and was caused by fluid off the aircon getting into one of the control boxes in the passenger footweell when parked om a slope. Dried out the box and all was well again and never done it since.

[NWTony]

I went to Maplins and bought some diodes and as if to mock me the fault has cleared itself. On the bright side I'm now an expert at breaking into TVRs.

Thanks again for the help, I'll check out the alternator at the weekend just in case.

[NWTony]

Session said:

My car did this whilst in france a couple of years back and was caused by fluid off the aircon getting into one of the control boxes in the passenger footweell when parked om a slope. Dried out the box and all was well again and never done it since.

May be that, it did happen after it pissed it down although to be honest I didn't see a lot of water around the footwell or electrics. I'll add waterproofing (bagging up) everything to my list of jobs just in case.

I have just had a new windscreen so I thought it might be possible that water was running off somewhere it didn't used to.

Ah the joys! If it weren't for absolutely everything electric this car would be no bother at all.

[NWTony]

hmmm, battery reading about 13.8 to 14.2, not varying with the revs though. Could well be the alternator after all. I'll give the diode a go.

Every day is a new adventure.

[SergSC]

NWTony said:

hmmm, battery reading about 13.8 to 14.2, not varying with the revs though. Could well be the alternator after all. I'll give the diode a go.

Every day is a new adventure.

13.8 is fine.
You have water ingress coming in somewhere. Any kind of short will drain the battery as well as the dash being on. If you press the brake pedal it will go off. In my case I wedged the brake pedal on.

In my car this happens only after heavy rain. I found a copper corrosion drip mark coming out of a relay connection at the back of the fuse box, the relay was also green.
Take them out one by one and have a good look.
To sort (until the next heavy rain) Contact cleaner and WD40. Go for a drive with the heater On and open/aim driver footwell vent at fuse box. It will sort itself as the moisture dries out.

Ive had a really good look and feel around the area and cant locate the source of ingress, despite taking the pod out (two alan screws under buttons either side), and despite serious contortion gymnastics in the footwell (picture taking a shoe off to unstuck).