All of that I learned in my last adventures with my alternator. And I have now verified that the D+ wire is continuous and the bulb is fine. So, that leaves that whatever is on the alternator side of the D+ post isn't working properly.

So, I dropped out my alternator again. I have torn it apart as far as I have figured out so far--but I haven't been able to get to where I could see what the D+ post hooks to to verify if it is still making a good electrical connection. So I am trying to figure out two things: 1) How does the alternator disassemble so I can see where the D+ post hooks up electrically? A exploded view of the alternator would be nice. I've looked around on the web, but I'll try again. 2) What does the D+ post actually do? I know it is an essential part of charging, and the system will not charge with out it. But why? It is a lot easier to trouble shoot things when you understand how they work.

I will post back here my findings.

 

Okay. Found an explaination for the why:
I found this here: Pelican Technical Article: Alternator System Troubleshooting

So far as I can tell the DF is an internal thing--it hooks up to the voltage regulator and is controlled that way. The only external outputs are D+, B+ and the ground.

That source also states:Conclusions: I still need to determine if the D+ is electrically sound. The clue about the B+ and D+ terminal may help me figure this out.

 

yeah, its internal. an alternator has two windings, the field windings (stationary, outside) and the rotor windings (rotating, connected via the brushes). "DF" is one of the brushes, D- is the other. btw, whats drawn as a relay in that schematic is, afaik, solid state on modern bosch alternators. "C2" in that drawing is the regulator/brush assembly. the 3 black rectangles in a 'mercedes logo' arrangement are the field windings, and the circle with the G in the middle is the rotor winding. B+ is connected to the 3 field windings via what is effectively a 3 phase full wave rectifier

 

Thanks for the info, pierce. I did end up reading that a few more times, and it all ended up making a lot of sense. The problem was inside the alternator. I had a little trouble getting the alternator rotor out, but when I finally got it out, I inspected the area where the D+ terminal was. This is what I saw:



At first, it looked fine. But then I looked closer.



Sure enough, the connection between the wire and the bolt head that is the post for the D+ terminal was broken. It probably broke when I twisted the head to try to loosen the nut for the D+ terminal spade. Although you can tell that the head is supposed to be held in place by that plastic piece, it seems to have either pulled below that or something like that, and now spun freely. Well, freely is an exaggeration. It is very difficult to twist, but twisted nonetheless.

So, I soldered the connection back on. It was an awkward solder--it is hard to heat up the head of a bolt enough to accept solder with only the tip of an iron... but a lot of patience, and I got it all together. It was not a pretty solder, but it was electrically continuous, so I was happy. (With as much soldering as I seem to do, I'm thinking I ought to get a better Iron with interchangeable tips...) On the other side of the post, I used a double nut configuration tightened against itself to hopefully hold everything in place. Then I put the spade on with a third nut & lock-washer.

Alternator back in the car... instrument cluster back in... tested it, and everything worked--battery light came on, car started, and voltage gauge read about 14.5 Volts.

So, finally, I have all my gauges working in the car, and the alternator works.

 

if you get a better soldering iron, get a 'temperature controlled soldering station' like a Weller. I've got the old style weller, that uses "PT" series tips that have a magnetic thermostat in them... different tips operate at different temperatures (a 7 on the bottom of the tip means 700F, 6.5 == 650F, etc). you use a bigger tip for working with heavier stuff, and a thin sharp tip for PCBA work. there's newer stuff available now.

 

Maybe it is just that the last few weeks have been unusually hot... maybe it was my chancing upon a volvo 240 greenbook that details how to rebuild the air conditioning pump... or perhaps it was stumbling upon a link that talked about HC12/Duracool and noticing that it was not illegal in West Virginia... or perhaps it is the fact that i have spent the last two weeks re-wiring all the dampers in a buildings air conditioner unit, but in any case, I am back to thinking about the air conditioner in my car, or rather the lack thereof.

As I mentioned, I recently found a Greenbook for the 240 and in the right era. (well, actualy Titan Joe did, and passed it onto me.) The greenbook had some interesting things: First, it had a timeline that showed all the changes in the air conditioner system from 1975 to 1992 (when the greenbook was published). What struck me was that it noted that from 1985 on, all ac units now had a ****. Like in the picture below.


My car has no such ****, but only a rocker switch that is either on or off. So, I will be investigating this. I'm curious about the function of the ****--does it cause the AC unit to cycle differently? or simply add heat like usual? I'll see if the greenbook is revealing in this.

Anyway, I haven't much time to post, but i also found this link:

Charging your A/C with refrigerant grade propane; cooler, slightly more explosive! - VW GTI Forum / VW Rabbit Forum / VW R32 Forum / VW Golf Forum - Golfmkv.com

The seem to indicate that in some states HC12/Duracool is not illegal. Including WV. With instructions on how to rebuild the AC and how much oil is needed etc, this is an option I will be investigating.

 

our 87 has that ****. it sets the duty cycle of the compressor. turned to 'max', you get full AC. turned just above 0, the compressor runs for a bit, then off for a longer bit. etc. afaik, there's no thermostat or anything.

 

First off, thanks for the info. I wondered if that was its purpose. In general, I operated under the assumption that car A/C's ran continuously. In my old 740T, it only had a lever that increased heat. Now, it may have not done that when set on AC, and only controlled cycling, however, at least I know how it works on the 240s.

The greenbook has been less informative than I had hoped. it only gives wiring diagrams for the AC up to 1987... yet on the back, it is clearly a 1992 printing. I guess they just didn't bother to update it? Hum.... Maybe I'll have to brake down and get a Bentley manual...

Anyway, the main reason I decided to post was that probably a month ago, my odometer quit working. Yes, AFTER i put in that new chip. The speedo continued to work. So, today, I pulled it apart. The problem was apparent--broken speedometer gear (who knew?). So I guess it is off to davebarton to order a new one. Will post back on progress both of AC and odomenter, although the latter ought to be pretty routeen.

 

there's a seperate greenbook wiring diagram for nearly every year of the 240, and usin gan old one on a newer car only goes so far.

I have the VCOA/OTP DVD full of greenbooks for 240s, lets see what I can find... this includes a LOT of info, not just electrical.

ok, the '240 new car features for 1991' greenbook says they used a new AC control system based on the 700's, rather than the older 240s, and its 50% more efficient. new evaporator, electric cooling fan on the engine. and yes, an on/off AC switch, instead of the old one.

greenbook "wiring diagrams 240 1991 (TP-31767-1US) shows this AC switch on page 118. the light in the switch goes between black (to ground) and grey-red (goes to the LH ECU pin 15, also to the AC relay), and the switch goes between that same grey-red and light to the blue-yellow wire which goes to the AC relay, and to fuse 12.

sorry, I can't screen-capture or PDF-print these pages, as this copy of the greenbooks is copy protected rather well.

 

Good to know about the wiring for the AC. And good to know I am not missing anything. I was curious if the car had had something strange happen to it... and have it's AC replaced with something 10 years older? This makes a lot more sense.

Of equal interest to me, I checked out VCOA's website and found the DVD you spoke of. Although it is $65, I think I'll spring for it. I had a complete greenbook set (hard copy, actual paper, bought at the time the car was purchased form Volvo) for my 740, and I found it to be incredibly handy. So I will probably go for that. I'll probably have to post fewer questions, but also contribute more meaningfully to some of the other questions on the forum, whereas most of the time, I just have to sit on the sidelines, and see what people say who know what they are talking about...

Along other lines, the new odometer gear is on it's way...

 

I am a little behind the times. Update:

I installed the new odometer gear, and adjusted the mileage to match roughly what it should be. I am running through the first tank of gas now so I can figure up the mileage. I haven't had a working odometer long enough to get any real feel for what mileage it gets in different conditions. The few times I have been able to take mileage it has been right around 24 mpg. I guess that is good. The old 740T got that kind of mileage when it was young, and it also had a manual. This one has not turbo and an automatic. I figured it would get around 22. Still, I haven't worked out the mileage enough to actually get a good average. We shall see.

I also got the Original Technical Publications from Volvo for the 240 series. Boy, do you have to jump through hoops to use it though. Still, it seems pretty cool, but I've not yet looked through it extensively. I did look up the section pierce pointed out... and that helps. I am considering printing the whole manual out, as I like paper copies better... but not immediately.

Anyway, that is where things stand.

 

annoyingly, printed pages from those OTP disks have a bigass Volvo logo watermark in the middle of every page. if the page scan quality is so-so like some of the older stuff is, the watermark can make it rather hard to read. still, its much cheaper than a full set of real green books.

 

I bought a set for 240's and for 740's. I thought the scan quality was atrocious. I returned them.

 

the 9xx one is fine. the 240 one is better than nothing. some of the older docs aren't that good, but the newer ones are fine for me.. there've only been a few I had trouble reading.

 

I was just really disappointed, knowing how legible the Green books are. And, disappointed that Volvo didn't go the distance; I felt they were essentially abandoning the 2's. Zooming in and printing seemed out of the question...and they ain't cheap. Given the quality of my budget scanner at home, I honestly could have done better.

 

my biggest gripe is the locklizard nonsense viewer. I have thi stuff installed on my home desktop, which I frequently use remotely from my laptop via remote desktop. well, locklizard refuses to run with RDP. so I ahve to be sitting at the desktop console, meh. and then its draconian blocking of any software that might be able to screencapture, I have to close my photoshop and lightroom to load it (normally those programs stay loaded for days, as I'm always diddling photos). the 9xx disk is still worth it. my 7xx is a 92 740 which virtually is a 92 940 sans some options, so I figured the 9xx disk was more useful as the odds of me getting an older 740 are a lot less than getting a newer 940 going forward. I've mostly been looking at the wiring diagrams of various cars.

 

The scan quality of the 240 stuff I've looked at has been fine, so far as I can tell... but most of it has been the later 240 stuff (for 1991, as it pertains to my car mostly).

But Locklizard is a pain in the butt... and I really dislike how the OTP program opens and then takes up the whole screen... but then doesn't show up on the taskbar... And more to the point, I really rather dislike all the restrictions on its use...

It has in it some things I had not been able to find online. I had visited kjet.org and downloaded most of the information they had there, but things like the 1991 new features (which was very informative) I could not find.

The annoying thing is every now and again, it will say "see 700 series books"--particularly about the air-conditioning. The good thing is that I still have access to 700 greenbooks that came with the 89 740T I used to drive... the bad thing is that it is across the country...

Back to AC, I want to take it out and check out the compressor & see if it functions at all or if it is pretty well shot. The problem is that the power steering belt comes off the AC in one of the stranger belt configurations I have seen. So, I'm trying to figure out if I can re-route the belt directly to the Power steering for a while, while I work on the compressor. I think this may work if I take off one of the belts from the alternator. But would that allow the alternator to slip? I figure it has two belts for a reason, but perhaps not... I'm also going to figure out if I can do this with existing belts. I'd rather not purchase a new belt just so I can temporarily re-route.

I saw a lot for sale earlier this year for 2 B21 engines, one of which came with a special piece for just a situation where you would remove the AC but still want power steering. Kind of wish I had that now.

 

I'v toyed with creating my own index page to the docs so I could blow off that stupid OTP thing entirely. would be a fair amount of work. someone has done the equivalent for the Mercedes Benz CD, as the supplied launcher software is much worse than this OTP thing.

 

The screws that hold the sunroof crank in place (& the gear and everything) keep coming loose. I need to get some thread-locker on the screws... but just keep forgetting to pick it up. Anyway, it got loose enough again that when closing the sunroof, the handle jumped a bit, and the sunroof got off.

So, I took it apart to fix it, and made an interesting discovery. It turns out, the sunroof was a little crocked--the passenger side was slightly more forward than the drivers side. When it got loose and the handle jumped, it made it worse, and that is when I noticed it. So, I dropped out the handle and gear, pushed the sunroof to the position where it starts to push down the little shield thing at the front of the sunroof, and put everything together. Now, it moves very easily in every direction, which it did not before. (I previously took the whole thing apart and lubed everything.) But I am pleased at the improvement now.

At this point, I just need to remember to pick up some threadlock, and then It ought to be in good shape.

Been busy... no progress on AC...

 

our 1987 240, we'd had a lot of problem with those screws, finally stripping... so I took the next size up fine thead metric tap, and retapped the holes for a larger screw, that lasted until the sunroof mechanism got so stiff that it wouldn't open or close without a lot of fussing, so I pulled the crank handle off entirely. I don't really want to pull the headliner off that 35 year old car to properly repair the sunroof, I'm afraid the headliner won't go back on nicely.