Gus

OK - Here is the latest update
It appears that the alternator was the base problem - on the way to work today the battery caution light came on, which means no output from alternator. The speedometer doesn't work and several gauges are in the limp mode - only half register - i.e. oil pressure only comes up about half way 2 1/2 vs norm 5 - guess this is all due to low voltage output-
I have to assume that I am running off of the battery right now -
Have not had a chance to check issue - Can't do much until I get the beast home -
Am thankful it is a short commute to work and back-

AB-Oz

My C4 sleeps conencted to a trickle charger, if not it drains the battery after about 2 weeks. The PO changed some wiring so that the electric windows and sunroof can be activated while the ignition is off.

I still haven't found where in the wiring this has been done, but if your electric windows work while engine is off maybe thats the source of your battery drain?

Gus

Update -
I pulled the alternator last night - have taken it to an alternator rebuild shop - local - and it should be ready this afternoon sometime. -- Rebuild is going to run around $75.00- (half of a new rebuilt)
So if all goes as scheduled - this evening I will put the alternator back in - and hopefully all will be back to normal -

Rally Guy

Gus - sorry to revive this old thread - but a pal and I are chasing VERY similar problems on a C4.

Was the alt the problem?

The Stig

Thanks for reviving this RK. I'm the pal in question.

I've gone through everything mentioned here and in Adrian's book. All fuses (front and rear) and relays have been pulled and replaced to see the delta in the draw. Nothing of major significance noted.

When connected to the DMM, it's pulling an 18.5A+ reading. Yes, 18.5A. The battery is brand new and fully charged. The battery goes flat in about an hour once connected to the car.

Two interesting things to note. When the battery is fully charged and connected to the car, there is a faint smell of burning/smouldering from the passenger side of the engine compartment. I can't pin point it exactly, but it's there.

Second thing to note is that the check engine light has been on for about 6 months. The hammer reads intermittent Hall Sensor effect. You can read about that in my previous post.

https://rennlist.com/forums/964-foru...e-machine.html

I have a sneaky suspicion the CEL is related to this draw some how. Alt is a Bosch Reman unit with maybe 7500kms on it. Still under warranty (thankfully).

Next step is to pull it into a shop I think. Can't think of what else to do. Will update when I have news.

Cliff

mojorizing

Cliff,
You've might have seen this post but 18 amp draw ( probably not on a protected circuit, but upstream of the fuse panel) and the smell of smoke in the passenger side trunk reminds me of the trouble Duck had....

https://rennlist.com/forums/964-foru...luck-ever.html

and the repair....

https://rennlist.com/forums/964-foru...he-repair.html

Let us know what you find.

The Stig

Thanks for the links mojorizing. I've searched extensively, but didn't come across them.

Gus

For my situation, YES - the alternator was the problem. Had it rebuilt for $80 and re-installed and problem was solved

HiWind

thanks!

bmohr

I finally came across and around this issue. Long coming I suppose. Had a battery drain, but disconnected the ccu fan and had the rear blower removed and jumpered the relay. All good for a long time, but it was a daily driver. Once I parked the 64 and drove another car to work it got mad at me apparently and drained the bat. Got a new one and it happened again. Tested the bat, got 12.6 or so. Tested the draw with ign off and got 25 mU. Then tested the alternator and got slightly above zero...so does that make my issue an alternator then? I"m a bit confused but I think I have everything sorted. I re installed the blower, relay and plugged back in the ccu fan and still I only have 25 mU with ingnition off. hmmmmmm

D.C.

I am having similar issues, intermittent current drain.

Adrian's book talks about checking the diodes in the alternator by testing for Alternating Current across the battery terminals. Anything over 400mv is to much and indicates a one or more bad doides

I am not sure I totally understand this, but it does make sense. If a Doide was fried and allowing current to flow in both directions, you would have AC across the battery terminals. This might also cause a current drain.

jody stowitts

You're not getting the "quick double-blink" on the red door lock post lights (immediately upon locking) that indicate a fault are you?

HiWind

I get a normal blink on lock and alarm does arm.

mc_renn

i had a similar issue earlier this year after replacing a failed cooling fan bearing I also installed a rebuilt alternator and a new battery. Battery drained after 2 days. After pulling my hair and saying the f bomb a couple of times I thought I check the door lights. Those little things that turn on the interior lights when the door is open. I took them both out, gave them a nice cleaning and made sure they worked and voila no battery drain. The car has sat over a week and no problem starting.

ToreB

bmohr, if the CCU with fan does not shut down as it should, it's probably due to a defective transistor inside. It's a 10-minute job for a guy with some experience with a soldering iron.
Disconnecting the CCU fan will not shut down the internal circuits of the CCU, so changing the transistor will be the best way to solve your problem.
The CCU will shut down immediately if the ignition has been on for a few seconds only, and will stay on for up to 20 minutes if the ginition has been turned on longer. Could this be the behaviour that makes it difficult to measure the drain in your car?
Cheers,
Tore