namespace

I have been monitoring this for 2 or 3 weeks now, heres what is happening.

about 2 or 3 times a week the battery goes dead (less than 5 volts) and the car wont crank. The battery has a sticker on it saying "Warranty replacement Aug 05", so its quite new, this happens after letting it sit for extended periods (i.e. overnight). I end up rolling out for a clutch start

[Voltage]
When the car does turn over normally (I dont use the accelerator to juice it up) I notice the voltage gauge sits at under 10 volts, only occaisionally the alternator light will come on when this happens, the car idles fine and as soon as I touch the accelerator, the volts jump to normal (13+), if the alt light was on, it goes out. Daily driving duties are unaffected, it starts normally all day, even after 2 or 3 hours sitting.
It has plenty of power to turn over the engine and volts and alternator all show 'good to go'

[Power windows work, no key]
the other day I had something different happen, the power windows were operational, without key in the ignition, this has only happened once, it stopped after moving the car to the garage. no other power stuff was able to be operated, without key in.

[Fan run on]
Today I took it out to do a job down the freeway, a 170km round trip, temp sat at half or less the whole way, and only got to 3/4 when idle, again, parked car in garage, shut her down, removed key and the fan was on, but not loud or full speed, it powered off after about 5mins this has happen twice since owning the car (2 months)

[suspicions]

Can anyone confirm my suspicions on these happenings? I suspect:

Alternator and/or possibly earthing

Temp sensor switch in radiator on its way out

Ignition switch assy. (I have already swapped out the cylinder lock to cure another minor issue)

battery may be in fact foobar (but I doubt it)

The problems are only minor in terms of annoyances, and I have complete faith during a normal days driving that the car will start, but I am concerned that a flakey ignition switch may short out and cause a fire or other electrical damage. to be safe, I am diconnecting battery overnight, when I do this, of course, it never goes flat.

any help appreciated, TIA, Adam

Bart

I assume this is on a '62 Mack truck, right?

peterr

I have extremely limited technical ability so take with a grain or two of salt...

I think your suspicions about electrical issues regarding the alternator or ignition system are worth pursuing. I doubt its your radiator temp switch, but I would not totally discount the battery.

I don't think it's your radiator temperature switch failing. The one on my 951 went about 4 days ago, and the fan will run on forever if i don't pull the G10 relay. I am getting the part and doing a drain flush and replace next week. Even after it ran on for a few hours at constant speed it did not drain my battery, which is about a year old.

The previous battery had barely made it out of winter storage and was sulfated. At first I could charge it back up and it would be fine for a while. Then it would drain down overnight. Then it would drain enough during the day that when I left work in the evening i needed a boost. Then it would last about three hours. Finally it would not take a charge at all. So while its hard to diagnose, I would not discount the possibility that your battery is beginning a death spiral. Was it stored for the winter?

On a previous 944 I had an issue where a fan would cycle on after shutdown but it was not the radiator fan, but the little electric fan. The issue was a blown resistor PN 944 616 521 00.

namespace

bart - its a '36 Ford pickup

namespace

Peterr - I have limited technical ability on these cars, thats why I am on this board, so I appreciate your comments and trying. The problems I am encountering, I am only going by what I have read from others (re: fan temp switch), so its hit and miss. I might just bite the bullet and buy another battery (regarding draining), as it would be the easiest thing to swap out, then continue diagnosis. voltage does indicate a normal charge rate, when driving/stopping/driving all day. its only when left for extended periods that it drops its volts. - so the ignition switch could be staying on and draining, even though key is out

Car doesnt get stored over winter, it rarely snows here and we dont use salt on our roads (I assume thats why people store their 'good' cars over there in the US?)

BTW - 84 NA

namespace

mmmm, I think I dislike electrical issues.....

peterr

Namespace

Yes, I am in Central Canada where snow and road salt are an issue 4 or 5 months of the year. I have winter driven my two previous 944's but this one has never seen winter and is rust free so I figured, why start now. I had just moved to a house where i have a 3 car garage too.

In general I would avoid buying a lot of parts before fully diagnnosng the problem. Particularly with electrical stuff its easy to get sidetracked.

On the battery issue, because I was going to store this car, I bought a battery trickle charger. I spent a few dollars more to get one that did diagnostics so it allowed me to hobble along for a few weeks with failing battery charging it every night. It eventually reported the "this is too far gone" message.

In this neck of the woods there is a chain of stores that sell auto parts that will test your battery for free (under the assumption that if its bad you will buy a battery from them). Do you have something similar available in Oz?

namespace

Peter, I have been trickle charging too, but not with a 'smart charger', for the $80 it will cost me for a battery, I will do that, but reading up more, it seems to be electrical, pointing toward ignition switch?

Do me a favour too and make sure our Prime Minister doesnt make it home from his Canadian trip, he annoys me as much as Bush does!

cheers

Adam

KuHL 951

I'm not sure how far your diagnostic abilities go but have you checked to see how much drain 'dark or gray current' is on the battery with the key off? Most 944's will have between a 20-45 mA drain. Some after market alarms and stereos are notorious for causing larger drains from failed components. A few areas that seem to be a problem are the window wiring through the doors at the frame(worn wiring), small cracks with high resistance shorts in the positive wiring from the battery to starter/alternator. First thing I would do is put a volt/ammeter on there and check the drain, if current drain is higher than normal start pulling fuses one at a time and watch for major changes in current. If you find nothing by the fuse method the problem can be confined to the unfused wiring to the starter/ alternator, stereo, or alarm. If the dark current drains are normal you might just have a failing cell in the battery and the battery just won't hold a charge. Sounds like your alternator is doing OK since you can drive the car with a low battery.

Electrical troubleshooting is not fun or quick but it will pay off if you find the source of the problem.

dme

Follow Steve's advice. Also, I've found that once batteries have become fully discharged, they never hold a charge as well again. The five minute run on of the radiator fan is perfectly normal. Anything more then five minutes and I'd be curious. Obviously down here in Texas I get to hear the fan a lot more after a hot drive. The power windows will work after you turn off the car and before you open the door to get out. This is normal. I think your battery is the problem, but check the drain on it while parked with everything off.

Peckster

Love to help if we could, but we don't deal with these things the same as other countries.

First step is to get your battery tested at a place that sells them. Then check your alternator output, pay someone to do it if you don't have a meter. Don't start buying parts before you know exactly what the problem is.

namespace

Steve - Mechanically I am fine, have had many cars in my life (lost count at 40 rides) and tinkered with them all, but being mostly pre 80's, electrically, they were pretty basic, this 944 seems to be quite advanced for its age, I will whip out the old Fluke MM and start probing, thanks for the t/shooting tips, it will give me a good start.

Dan, so I can rule out fan switch, the power window thing doesnt work! - I have never been able to wind up as you describe, it only happened once, so I will probably have to look at ignition switch, other than that they work normally, fans and the noise they make, I will live with, it can get as hot as Texas here, but we're coming into winter now, which can get as cold as the northern US, without the snow, a new battery will help with the colder weather

dme

Sorry, missed the part about it being an 84. Don't know if the windows worked the same way on the pre-85.5 models. Also missed the part about Australia. Damn, I've got to quit drinking tequila in the afternoon.

mortymower

Im not sure if the windows work the same way on the pre 85.5, but if they do, you might have the same problem i did. They are only supposed to work until you open the door, but my door switch was corroded and only worked sometimes, therefore when it did not work the car did not realize that i had left and when I came back, they would still work with no key. Cleaned the switch and good as new