Hello there and welcome to the BMW Car Club of America.

If you are a BMW CCA member, please log in and introduce yourself in our Member Introductions section.

1987 325ic: Instruments & A/C both abruptly stopped working

Discussion in 'E30 (1984-1993)' started by Brian A, Sep 14, 2009.

    • Member

    Brian A

    Post Count: 657
    Likes Received:7
    I've recently returned home from a 1 week, 2,200 mile road trip in my 1987 325i convertible. It was a tough trip for the car (10,000 ft mountain passes; 110F desert temperatures, long days, etc) and undeniably, it had its problems.

    One problem I need help figuring out.

    Somewhere in the heat of the Mojave Desert, headed toward the Grand Canyon, there was an electrical glitch. The symptoms now are:

    1.) All instruments in the instrument cluster - except speedometer - are dead (fuel gauge, water temperature gauge, tachometer and instantaneous mpg gauges are dead).

    2.) Instrument cluster shows ABS and battery warning after engine started (fades after a few seconds) (it's not the normal vehicle function "check" lighting while starting).

    3.) A/C compressor and blower fan activate when engine is first started, then shut-down after 2 seconds. A "sneeze' sound comes from the compressor when it stops.

    4.) OBC dumped its memory (time, date, av mpg, av mph etc) but now seems to be holding memory (time, date) but is not getting a signal for mpg, mpg or range.


    5.) Radio locked and required "security code" entry but held its memory.

    6.) Despite this all, the car runs like there is nothing wrong.

    Do these symptoms point toward suspect connectors, relays or something? All troubleshooting I have read treats the symptoms separately. It just seems too coincidental for it to be simultaneous failure of independent systems.

    Poor little car. It got me home despite its problems (and thank goodness for modern sunscreens).
    • Member

    granthr

    Post Count: 1,583
    Likes Received:2
    Sorry to hear about your troubles with the car. I would guess that it is the SI board. It controls all of the functions you mention that are not working. Also the OBC gets it's info from the SI board for the items that you say are not working. It is pretty easy to get to, I have pulled my fair share of instrument clusters. You don't really need to pull the steering wheel. The bentley manual walks you through this nicely.

    You can mess with getting new batteries for the SI board if you like, but it might be more than that. You can get used and recondition ones from advertisers in the back of Roundel. A while ago I bought a used one for my 318i and it was $75.00, reconditioned was about $125, but you need a good core exchange. I went with used because my old SI had had a melt down sometime in it's life, so I didn't think they would accept it as a core.

    Not sure what to make of the radio issue though.

    The AC might be acting up because it might think the car is over heating. I would suggest getting the gauges to work and then see if the AC starts working normal again.

    Sounds like a great trip and it sounds like you got off easy. :D I just got back from a 3 week trip from Penna to Colorado, Arizona, Utah and many in between and then back home. We took our 325ix and it ran great..... till I spun a bearing! :( I guess it didn't like three hours at triple digits, 4,000+ rpms in the desert. We did make it from the North to the South rim of the Grand Canyon in record time though! :D

    The motor gave up a couple days later as were were headed to Zion National park from Las Vegas. We coasted into St. George, UT. Considering the bad situation, it actually turned out well. We broke down in a real town and were not stuck in the middle of no where. We found a great independent Euro shop. They specialize in MB, but work on BMWs too. We got a used motor with only 74K on it and were back on the road in a week. It was a long stay, but we were stuck and I didn't want to ditch the car. Fortunately we were in the process of moving and switching jobs, so there wasn't any hurry to get back east.

    Let us know how you make out.
    • Member

    Brian A

    Post Count: 657
    Likes Received:7
    Oh, maaaan! Sorry to hear about your car. You sound mighty philosophic about it all. That is admirable. At least it was adventure and adventure is good. For me, the Grand Canyon went better. I parked my car on the South Rim, took the shuttle van to the North Rim (4.5 hour ride) and took two days to descend down to the Colorado river and back up to my car. An amazing trek (back to a car with no A/C).

    I looked up the circuit diagrams for the A/C, and sure enough there is a high engine temperature cut-off. I bet you put your finger on the problem. I will pull the SI board tomorrow evening and sniff around. Hopefully its just a loose connection. I've pulled my Instrument Cluster a bunch of times and have actually moved the SI batteries off the SI board (http://www.bmwcca.org/forum/showthread.php?t=113) (maybe one of my dumb wires came loose). Bentley has a diagram to test the input/output pins for the main connector.
    • Member

    granthr

    Post Count: 1,583
    Likes Received:2
    Well it was a great trip across the country and we hit 6 National Parks. It was a risk taking our highest mileage BMW (172K when we left, now 179K), but I knew the trip would entail some gravel roads, so the 325ix seemed the best choice. It is also our only 4 door, which was also nice for all our gear. I am glad the new motor has 100K less than the old motor. I plan on keeping this car a long time.

    So what is a cross country trip without major mechanical problems. :D The car also ate a V-belt in Kansas on our way home, the water pump and alternator belt of course! Fortunately I had a spare with me, it was during the day, and the weather was nice. We were back on our way in 45 mins. I had the car shut down within 10 secs of the lights coming on and the temp barely got above half. So I don't think any damage was done.

    Sounds like you had a great trip. What a great experience hiking from the North Rim to the South! How hot did it get down at the river? We did some rim hikes on the North Rim and did hike down into the Canyon for about 4 hours round trip. It is amazing how quickly the temp increases as you descend into the canyon.

    When where you there? We were at the North Rim on August 14 & 15 and headed to the South Rim on August 16. (Three hours to get there by the way! :D)

    I hope your only issue is a loose wire! That would be great. Good Luck.
    • Member

    az3579

    Post Count: 3,270
    Likes Received:3
    What I don't understand is why would the AC not working be relevant to the instrument cluster not working??


    And about the water pump - well, I drove home about 60 miles on Sunday with absolutely no coolant in the reservoir. Turns out that my water pump (that I got from BavAuto :rolleyes:) failed on me and was slowly decorating the road and highway with a nice stream of coolant, or a nice small puddle when standing. M20's are tough sons-of-of-a-bimmer. How on earth did you manage to change those belts in 45 mins?? Is it really that easy? Gee, here I was thinking "I don't want to try doing that because it'll take me ages and I'll mess it up"... lol
    • Member

    granthr

    Post Count: 1,583
    Likes Received:2
    The car shuts the AC down when it over heats to prevent further damage to the engine or damage to the AC system it's self. So if the cluster is not working properly it could be telling the AC that it needs to shut down b/c it thinks it is over heating even though it isn't.

    I have done V belts many times now, I guess practice makes perfect. When you have three E30s you start to get good at things like this. Also when you are on the side of the road in the middle of nowhere Kansas and you want to get into middle Missouri by night you have motivation to get them changed.

    I must say I was lucking in that as soon as the belt failed I had an exit off the highway. So I was able to coast off the highway and onto a B road with almost no traffic. Quite a few people stopped to see if we needed help, including a Kansas Sheriff or State Trooper (not sure what he was). Everyone was very nice. I am sure it was a bit of a scene to pull up on. A guy under a car along side of the road with his tools laid out and intake pumping and plastic pieces on the ground. :D My wife was kind enough to take plenty of pictures so we would forget. :)
    • Member

    Brian A

    Post Count: 657
    Likes Received:7
    Thats the theory; we shall see if it is the reality.

    You certainly win the Roadtrip 2009 Survivor contest. I lost my auxilliary fuel pump, my gauges, my A/C and wore my front brake pads down nada. Other than that, the car was fine.

    It was absolutely amazing. Hard to put in words. Yeah, temperture is a big issue. Forecast was 'only' for 100F at the bottom so I decided to go for it. I began descent of North Rim at 5:30 AM on Sept 02, arrived at Phantom Ranch at noon (14 miles; 5,800 ft descent). Slept on a picnic table at Bright Angel Campground (yes, I had a Backcountry Permit etc). Left next morning at 5:00 AM and was back at the car by 10:00 AM. Here are some pix:
    • Member

    granthr

    Post Count: 1,583
    Likes Received:2
    Yes it is just my theory. Just trying to explain my thought process to Botond. For your sake I hope that is all it is.

    Those pictures are great! The first and third one are very familiar. We were at those same places just a few weeks before you. The trail we took into the canyon was the North Kiabab trail. We made it through the tunnel, but not as far as the bridge that you can see in your picture.

    We stayed at the cabins at Kaibab Lodge, about 18 miles from the North Rim. We really enjoyed the North Rim, the people are different (nicer) and there is a whole lot less of them. :D Much more of a community feel compared to the South Rim. A local orchestra even played at the North Rim Lodge the one evening. it was great to watch the sun go down listening to the Lone Ranger, Whoopie Ti Yi Yo (Git Along Little Dogies), Ghost Riders in the Sky, and other great Americana classics. :D
    • Member

    Brian A

    Post Count: 657
    Likes Received:7
    Supai Tunnel is at 6,800 ft, so you descended over 1,400 ft into the canyon. That is a fair ways. I took N Kaibab trail too. Here is a picture that won't be familiar: The Colorado River at Phantom Ranch ("Silver" suspension bridge in background; picture taken from "Black" suspension bridge).
    • Member

    granthr

    Post Count: 1,583
    Likes Received:2
    Yes it was a far way down. :) Earlier in the week we had hike La Plata Peak in Colorado with my Cousin who lives there. That was tough too, but we didn't have to deal with the heat there.

    Hiking from one side to the other sounds great. We didn't really realize it was possible until we got there. Nor did we really have the equipment for such a hike. We had good day hiking equipment and overnight car camping stuff. Although I guess a picnic table can serve pretty well when pushed into service! :D
    • Member

    az3579

    Post Count: 3,270
    Likes Received:3
    Gawd, that is breathtaking; that E30 looks pristine! :D
    • Member

    Brian A

    Post Count: 657
    Likes Received:7
    Problems are resolved

    I have heard it said that people are stupid. I, being a people, am certainly capable my share of stupidity.

    Saturday morning finally gave me time to troubleshoot and resolve my dead gauges, A/C etc.

    BMW E30 Electrical Troubleshooting Manual shows that the E30 has a high engine temperature cut-off switch for the A/C. I tackled the gauges first in hopes that A/C would also start working.

    I pulled the instrument cluster and used the Bentley manual (Sec 15, Fig 7-1 & Table H) to check voltages in the harnesses. Everything checked okay except C1-23 (blue connector, pin 23) and C2-6 (white connector, pin 6) which were not energizing to 12V when ignition switched on. The smoking gun.

    BMW E30 Electrical Troubleshooting Manual shows C1-23 and C2-6 getting power from fuse 10. Pulled fuse 10; checked voltage across fuse 10 with ignition on. Fuse 10 was getting voltage. Problem was between fuse 10 and instrument cluster.

    To be triple redundant, I set multi-meter to Ohms and checked resistance of fuse 10. Open circuit!!!! Got my magnifying glass and discovered #@$%$ fuse 10 was actually blown. Replaced fuse 10. All normal vehicle function has returned.

    Oh the Humanity of it all. I cried, then I laughed, then I cried again.
    • Member

    az3579

    Post Count: 3,270
    Likes Received:3
    Oh, you crazy people person. Even I could have figured that out... :D
    I actually found a dead fuse in my car the other day and had absolutely no idea what it controlled. lol

    Autohaus guest

    Post Count: 1,571
    Likes Received:1


    Even I knew it was the fuse :). Good thing your E30 is back on track.

    NOS :confused:
    • Member

    granthr

    Post Count: 1,583
    Likes Received:2
    It is always amazing how a big problem has such a simple solution and how people almost always assume a big solution and forget to check the small possible solutions.

    Well, there are two bright sides to this. One, at least it was just a fuse and you didn't have bigger issues. Second, you were just fine tuning your trouble shooting skills and knowledge of how your car works. Just look at it as an exercise of electrical trouble shooting with a valuable lesson at the end! :D Always Always check the fuses first! :)

    Glad to hear you got it working.
    • Member

    Brian A

    Post Count: 657
    Likes Received:7
    ... or not.

    Fuse 10 blew again today. Something bigger is wrong.

    I HAD checked the fuses before I dug into the trouble shooting.

    I was taking solace in just being stupid. Now I have real problems to deal with again.
    • Member

    granthr

    Post Count: 1,583
    Likes Received:2
    Sorry to hear that the problem is back or should I say still with you. Let us know what you find out.
    • Member

    Brian A

    Post Count: 657
    Likes Received:7
    I have fixed my car.

    The reason why my air conditioner wasn't working was because I had an intermittent short in my backup light circuit. This is the most Byzantine interrelationship I ever seen in my E30.

    The backup lights are powered through fuse 10. So is the instrument cluster. Once in a while, when I put the car into reverse, fuse 10 would blow. This would cause the instruments to go dead. There is a "hot engine" cut-off relay on the A/C system. When the instruments went dead, they caused the "hot engine" relay to open. My A/C would die.

    The difficulty in the diagnosis was finding the correlation between putting the car in reverse and the fuse blowing. It only happened intermittently.

    The problem was with the pigtail harness that runs to the backup light switch on the transmission. It had drooped onto the driveshaft and cut open. A little solder, a short length of heat shrink tubing, a bunch of electrical tape, and I was back in business.

    Arash2002tii guest

    Post Count: 235
    Likes Received:0
    It's for the VTEC solenoids
    • Member

    granthr

    Post Count: 1,583
    Likes Received:2
    Brian glad to hear you resolved your issue. I know it feels good to resolve a tricky problem like that.

Share This Page