QuestionDear Tom,
I've been saddled with a nightmare of what seems to be very well hidden short in a 1980 Oldsmobile Cutlass Coupe. I'ts equipped with a Chevrolet 305-V8/4bbl, automatic, A/C, PWR seat/windows/locks/tilt/Rear defogger. This vehicle was purchased new, is personnaly known to me, has always been garaged, and never been a home to mice.
After hours of employing short finding tools and techniques in obvious areas, dash removal and instrument cluster/control switches inspection, wire harness (underhood, throttle linkage, starter, and exhaust areas, firewall, underdash, body), fuse box assembly removal/insp. and re-installation, alternator replacement, I still can't locate the culprit!!!
The problem is that at rest (vehile standing still, engine not running, key forward in the run position) all buzzers and dash warning indicator lights) operate properly. With the engine running (on/off idle), regardless of vehicle standing still or in motion, two minutes or ten minutes of operation, from cold start or warmed up, one of the two twenty amp fuses located in the fusebox labled instrument panel will randomly blow. When this happens, the instrment cluster panel charging system failure indicator light will illuminate (with a faint glow) and the door/seat/key buzzer is apt to fade in and out. If the fuse is replaced immediately (engine running/engine off), "normal" indication of circuitry operation is restored however, temporary. Correct alternator output is still maintained (never discharge/alternator and battery were replaced), all buzzers, dash control swithes (i.e. A/C, rear window defogger, etc.) have been disconnected, and process of elimination through disconnection of shared circuit accessories has not revealed the cause. I've looked for poor grounds in just about every place imagineable thinking that when the circuit is compomised, possible reverse flow of current results in charging system failure indicator glow and intermittent buzzer operation. The vehicles driveability is never negatively affected and I refuse to grant the customers wishes to disconnect buzzers/remove indicator lights as a resolution to this problem. Thanks in advance for your advice.
AnswerShort circuits are very easy to find and iF I had the vehicle I could have your short found in less than 15 minutes.
Unfortunately, I don't have access to the vehicle.
Did you try unplugging the cigarette lighters as Olds is FAMOUS for having delayed short circuits in their lighter sockets.
Does the vehicle have ANY emission control system on it ?.
If it does, locate the CHARCOAL CANISTER CONTROL SOLENOID , Unplug it and see if your problem is resolved. If it IS, replace the solenoid.
Where is this vehicle located ?.
Also, What mechanical work or ANY kind of work has been performed on the vehicle recently ?. As most problems that occur after a recent repair was made can be traced back to the area of where the repair was made as a wire connection came loose, or is shorting against the engine block. Look around in the area where work was performed.
In a lot of cases this type of short is traced to an emissions solenoid when the vehicle goes into the CLOSED loop portion of the computer system which is when the charcoal canister and the solenoids for the emissions sytem activate after about 5 to 10 minutes after the engine has started.
You may also want to unplug the electrical connector at the transmission and see if you problem is resolved.
let me know.
autohelp
autohelp
