Electrical problem in 9000

I recently had my 97 9000 Aero in for repair at my excellent local repair shop. I had them replace the ignition switch in the steering column. While there, I asked them to check the electrical system generally because of something I'd noticed. As I'd drive down the road, I noticed that the voltage on the dashboard indicator would go up and down. Anywhere from 11 volts to 14.2, usually up around 14 where it belongs. They found that the alternator was putting out considerably less than the correct amount so I had them replace it. I still have some fluctuation in the reading on the gauge but much less than I used to have. But, as I drive along, I do notice a dimming of the headlights from time to time. No new load (like an a/c compressor) kicking in, just driving down the road. The lights come back up to normal brightness in a few seconds. The shop is aware that the voltage still isn't right but none of us are sure where to check next. The battery is about two years old, on a 60 month Interstate battery.

Anyone have an idea on what might be causing this fluctuation in the voltage?

Thanks.

Reply to
Milo
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Two items I would check would be the light switch itself and the headlight relays - also the wiring going to each of them around the points where it meets the connectors and the relay panel. I am not certain, but I believe that the usual failure mode for the headlight relay is simply no light at all from one or both of the lamps, usually the high beam - but still it is not a bad place to start. What usually happens is that the relay itself is not bad but the solder joints begin to fail in the relay board where the contact pins that connnect the relay to the relay panel (this is in the box in front of the battery, not the panel above the fuse board under the airbag in the passenger footwell). Typically the relay problem can be solved by simply re-flowing the solder joints with a low watt soldering iron and maybe a bit more electrical solder - but as I said, that failure usually isn't one of dimming and brightening.

Reply to
bozo

My favorite item to check is the main feed to the relay panel above the passenger's feet. A large red cable (from the battery) feeds everything on the panel and is secured by a nut and bolt that can, over time, loosen and cause a minor flickering (at first) which gets worse over time.

Walt Kienzle

1991 9000T
Reply to
Walt Kienzle

There's a broken headlamp filament detection circuit in relay type enclsiure in the 'relay box' in the engine compartment. The soldering can go bad and high resistance. I fixed one simply by resoldering.

Graham

Reply to
Eeyore

This makes a lot more sense than the headlight relay or headlight switch -

Reply to
bozo

Milo used his keyboard to write :

Check earth leads especially engine to body. Cheers Clive

Reply to
Clive Turnbull

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