odonnell

I did indeed end up ordering the 75 C along with a new washer for it. The current switch is going to stay unplugged until I need to drive somewhere urgently I guess

Arahant

Hi Guys,

Sorry to necro this thread but I figured why not keep all the information in the same place instead of making a new thread.

I'm having the same problem as OP, I put my 86 944 turbo away for the winter into storage, basically like 4 months... I went by and started it once during the winter but it mostly sat for those 4 months.. I don't recall if I had a problem that one time, but when I took it out of storage a few weeks ago the battery was dead. I boosted it with my cayenne, took it for a spin to get some gas, when i went to start it back up after getting gas the battery is dead again.

I'm not super familiar with mechanics, but I figured maby it was the battery, so I bought a new battery, but still had the same problem... it basically takes like 5-10 minutes for it to drain to dead. Normally when I turn the car off the fan will go for a little bit then turn off, I'm guessing it has something to do with the turbo, but now the fan goes untill the battery dies... also, when I boost the car, as soon as the positive cable hooks up to the positive on the battery the fan comes on, its the first thing you hear.

So basically I'v been having to drive around with one of those battery pack/booster things, which I bought for my cayenne in the winter but has been very handy to let me drive the 944 around.

I'm not super familiar with the mechanical side of things like I said, but if there is a somewhat easy way for me to fix this, I'd be willing to have a crack at it... I got a Haynes 944 repair manaul, aswell as I can look over the clarks garage site... based on what I'v read over the previous posts... I think I need to try and test/fix either the relay or the switch?

again sorry for necro but hoping I can get some help/advice on this to save me taking it to a shop thats abit over an hour away.

odonnell

In my case(s) it took several hours for the running fans to deplete the battery. I would park it at the end of the day, and when I went out the next morning completely flat. If your battery is dead after a few minutes (getting gas) I doubt it's the fan switch. After all it stays on for 2-10 mins after the car is off when operating correctly. I would make sure the alternator is even charging the battery, local auto parts stores will test for free if you ask them.

Another part the turbos have is that auxiliary water pump that stays on after key-off just like the fan switch. I'm not the most knowledgeable person on them, but you could probably find a test procedure somewhere using google.

And since posting this thread, I've had to replace the fan switch 2 more times (one was defective). I promised myself that the next time it goes bad I'm putting it on a relayed toggle switch and run it manually.

Arahant

It actually turns out that it takes longer for it drain then I thought, I guess the battery just didnt have much juice in it when i first boost it... if I drive around for an hour or so... the fan will go for a long time before it drains enough... but usualy I only drive for like 10 minutes at a time... so it drains real quick..

I'v been really enjoying driving the car since i got it back on the road, the other day I was out for like 1.5 hours just driving around... and I noticed when I came outside for something after I had parked her, that the fan was still going and this was like an hour later after parking her... so I guess it depends how much I'v been driving her... I'm pretty sure the alternator is fine cause once its boosted I can drive around no problem and I would think the alternator would have to work in order for that to be the case no?

When the battery is dead and I boost it, if I were to drive down the road and go into a store or get gas, the battery would be dead by the time i get out.... but if I drive for a long time it seems to last longer.... I still think its the same problem you had... I going to look getting a new fan switch..

Did you replace it yourself? is it hard?

snb13

They're not difficult. And if I remember correctly, an alternator won't charge at idle. Your using up the charge to start the car and then not driving far enough to replenish the charge.

mel_t_vin

Incorrect.

V drop across the terminals while engine is off should be 12.6v +/- 0.2v. V drop across the terminals while the engine is running/idling should be 13.8v +/-0.2v. That difference indicates a functioning alternator/regulator. Much higher/lower readings could indicate issues with the charging system.

Tiger03447

You should get Some charge out of the alternator at idle...not much, but some..the battery really needs to put on a charger, unhook the negative, and clamp on the charger.. if the charger is an automatic one, so much the better..that way you don't overcharge the battery..needs to be left on it for a day or two to really bring it up to a FULL charge...the faster that one charges a battery, the worse it is on the battery internals..remember, you are filling an empty 2 gallon bucket with a thimble..so it takes a while...