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98 Bonneville electrical/charge problems

Let me begin by stating I am new to alot of this so if I say something ignorant, please bear with me. :)

I have a 98 Bonneville and have been having electrical problems. It started about a week ago when I was driving down the road and suddenly the car just died on me. All electrical was gone and the engine stalled. I pulled over and turned the ignition off/on. Now the car wouldn't start (not even a click from the starter), but the ac/heater blower, interior lights, headlights and taillights worked. The radio would not come on. We hooked up jumper cables and still the same result, we had interior power but the starter wouldn't click. In addition, when turning the ignition key the interior lights would not turn off momentarily as they normally do when starting the vehicle. Upon examining the battery I noticed that the positive terminal was stripped and it was impossible to get a tight connection to the battery. Since I had a warranty on the battery I went to autozone and got a replacement. Upon installing this new battery, the car started right up.

I knew there was probably more to this since just a bad battery wouldn't cause the car to die on me when driving. I took the car for a test drive and noticed the voltage meter constantly fluctuating. So I lifted the hood and could hear a whine noise coming from the alternator. I decided the alternator was probably bad so I removed it. My rationale was that a bad alternator AND a bad battery could cause the car to die on me as it had. I go to autozone and the tech bench tests it and says it is totally dead. From what I observed on their gauges, the alternator generated no power. So I buy a new alternator and install it.

Now i'm still having the same problems. The voltage gauge is constantly fluctuating from 14V down to the red zones. It's not just a broken gauge because when it does get low the blinker rate slows, fan blower slows, lights dim, etc. When it gets real bad the gauge will be on ~12 and if I just touch the power window switch for a second it drops way in the red. Yesterday I drove about 15 miles with the voltage showing in the red (i'd guess between 9 and 12V). When I got home I immediately got a multimeter and tested the battery. It showed 12.5V cold. I started the car and the battery read a solid

14.5V with brights on and heater blower wide open. Meanwhile, the dashboard voltage gauge was showing from 10-12V at the same time. This leads me believe my charging system is actually working fine and I have a problem elsewhere.

The voltage regulator is built into the alternator so I know it can't be that. I now even wonder if the tech at autozone even tested my previous alternator correctly. It did feel like the bearings were going bad when hand turning it, but i'm still not sure i needed a new one.

Does anyone have any ideas where to check next? I just sank $1700 into a major engine repair and really want to resolve this on my own. Thanks in advance for any advice.

Reply to
shaggz
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shaggz wrote in rec.autos.tech

First of all, if the bearings felt bad then they were almost definitely going bad. You needed a new alternator from the sounds of it. As to your other problems, make sure all the connections to the battery are tight and clean. And this includes the ground connections and the connections at the solenoid and starter. And be sure to check that all fuses are tight in their sockets, and that the fuses are good.

If that doesn't clear up the problem use your volt meter to read voltages starting at the battery, going to the alternator, then to the ignition switch and fuse blocks. Get a wiring diagram for your car. It will be a big help.

Reply to
Dick C

Based on the age of the vehicle you could have needed an alternator too so I would not feel bad having a new one on there anyway. Your last paragraph could be the clue to the problem. During that major engine work they must have removed various grounding straps to the engine. First thing I would do is check them to see if they make a good connection. You might also run an estra ground strap from the engine to the body. Of course, check the battery connections at the starter and ground.

Reply to
eddy eagle

Also check to make sure you have continuity on the main alternator wire as well as the power wire for the alternator field.

Reply to
hyundaitech

Do you have two positive cables on the battery? If so corrosion likes to build up between the two causing similar problems. Take the two cables apart and clean up all four surfaces (two cables front and back). If the cable is swolen near the end you may have corrosion in the cable and need a new cable or new end.

Make sure the bolt is clean also and then put the whole thing back together. This should resolve your problem. If it doesn't or you have only one cable then start looking for ground problems as other posters here have suggested.

Steve B.

Reply to
Steve B.

I resolved the problem. There was a loose ground wire that was attached to the fuse/relay compartment. I hadn't seen it before. Now she runs like a charm.

Thanks a bunch guys!

Reply to
shaggz

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