Three parts later the fault is still there, because nobody followed the wire.
Electrical work rewards patience and punishes shopping. We show up with a meter, the wiring diagram for your vehicle and enough time to find where the circuit actually breaks down, instead of handing you a list of parts to try.
- Open 24 hours, seven days
- No hourly minimum
- Diagrams and a meter, not guesswork
- Cars, trucks, trailers and equipment
The parts cannon is expensive and it usually misses
Somebody tells you the battery is bad, so you buy a battery. The problem comes back, so you buy an alternator. It comes back again, so now it must be the starter. Two months and three parts later the vehicle is doing exactly what it did in the first place, and nobody has yet put a meter on the circuit to find out where the voltage stops. A circuit is a loop, and a fault lives at one point on that loop. Finding that point takes measurement, and it cannot be done from the parts counter.
What a trace looks likeConfirm the complaint, pull the diagram for that exact circuit, then measure voltage and voltage drop along it until the numbers change at one point. That point is the fault.
What you payYou get a real number before we roll, and diagnostic time is charged as the time it takes, with nothing added to reach a minimum.
Who we see mostWork trucks with added upfits, delivery vans, older pickups, trailers with tired plugs, and fleet units nobody has time to chase between routes.
Grounds are the first place to look and the last place people check
A shocking share of electrical faults are not a failed component at all. They are a bad return path. Current has to get back to the battery negative, and it does that through braided straps and small bolts fastened to painted sheet metal or an engine block. Those bolts sit in road spray. Around the Carquinez Strait they sit in salt air as well. Over years the joint under the bolt head builds a thin resistive layer that looks perfectly fine to the eye.
What that layer does is subtle and maddening. The circuit still works, just weakly. Lights go dim when another load switches on. A fuel pump runs slow. A blower only has high speed. Two unrelated things fail at once, which is the signature of a shared ground, and a technician chasing them separately will never land on the cause.
A voltage drop test finds it in minutes. You load the circuit, then measure between the component’s ground and the battery post. A healthy ground reads near zero. A tenth of a volt matters. Half a volt is a fault. Clean the joint, use a star washer, put dielectric grease on it, and two symptoms disappear together without a single part being bought.
The fault that vanishes the moment help arrives
Intermittents are the hardest calls and the most satisfying to solve. The vehicle misbehaved all week and then behaves perfectly while somebody is standing there with a meter. That is not bad luck. It means the fault depends on a condition: temperature, vibration, steering angle, a door being open, rain, or the engine being hot after a long pull up Highway 29.
So we stop trying to catch it by staring and start trying to provoke it. Wiggle test the harness section by section with the circuit live and a meter watching. Heat a suspect connector, or cool it. Load the circuit and see whether it holds. Where the vehicle supports it, we leave a recording meter on the circuit so the failure captures itself while you drive normally, then read back exactly when the voltage dropped out.
The reason this matters is that guessing on an intermittent is worse than guessing on a dead circuit. A dead circuit tells you immediately whether your repair worked. An intermittent lets you believe you fixed it for a week. Then it strands somebody. Have a look at the kind of calls we turn up for.
If the number on the invoice is different from the number on the phone, I did something wrong.
Patrick Freeman, owner
Where an electrical trace usually leads next
Diagnosis is the first half. Most of these pages are what the trace turns into once we know where the circuit is failing, and all of it is work the truck can finish on site.
Wiring repair
Once the fault is located, the physical repair: chafed sections, rodent damage, corroded connectors and cooked insulation near heat.
No-start diagnostics
Power, ground, fuel and spark checked in order, so an engine that cranks but will not catch gets narrowed properly.
Battery testing
Resting voltage and a load test, because a weak battery imitates a dozen electrical faults it did not cause.
Alternator replacement
Charging output measured at idle and under load before anything is condemned, plus the cable that feeds it.
Check engine light diagnostics
A stored code names a circuit, not a part. We read it, then test what it points at.
Heavy equipment electrical repair
Machines that live in dirt and vibration, where connectors and grounds take far more abuse than anything on a road vehicle.
How we work a circuit down to one point
The order is deliberate. Skipping straight to a scan tool is how a good module gets replaced because its power feed was weak.
- Get the story straightWhat fails, how often, and what else is happening at that moment. Cold mornings, hard right turns and a running heater are all clues that narrow the search before a tool comes out.
- Agree the number firstYou hear what the job runs while we are still talking, and if the trace turns up something bigger you hear about that before we carry on.
- Check the supplyBattery condition, charging output, main grounds. Everything downstream lies if these are wrong, and testing them takes a few minutes.
- Read codes as directionsCodes get pulled and treated as a pointer to a circuit. Then we go and measure that circuit rather than buying the part named in the description.
- Measure, do not assumeVoltage at the load, voltage drop on both sides, resistance with the circuit isolated. Each reading rules something out until one point is left.
- Fix it and prove itRepair, then reproduce the exact condition that caused the failure and confirm the readings hold. A repair that only passes at idle in a driveway is not finished.
What people want to know before booking a trace
These come up most. Anything not covered, the phone gets you a real answer in about a minute.
My battery goes flat if the truck sits for two days. What is that?
That is a parasitic draw, meaning something stays powered after the vehicle should be asleep. Common causes are an aftermarket stereo or alarm wired to constant power, a glove box or trunk light that never switches off, a module that will not go to sleep, and a failing diode inside the alternator. We put a meter in series at the battery, wait for the vehicle to settle, then pull fuses until the current drops. The fuse that drops it names the circuit.
The fault only happens sometimes. Is it worth calling you out?
Yes, and intermittents are a large part of this work. We do not sit and hope it happens. We try to provoke it by wiggling the harness with the circuit live, by heating or cooling a suspect connector, and by loading the circuit to see whether it holds. Where it fits the vehicle we can leave a recording meter on the circuit so the failure captures itself while you drive, and we read back exactly when the voltage dropped.
A scan tool gave me a code. Does that not tell you the answer?
It tells us which circuit to go and test, which is genuinely useful and is where we start. What it does not do is name a failed part. A code for a sensor circuit is thrown by the sensor, its wiring, its connector, its ground, or by a module that is not seeing what it expects. Replacing the part named in the code description without measuring the circuit is how people buy two sensors and still have the light on.
Two things stopped working at once. Are those related?
Almost certainly, and that is useful information. When two unrelated components fail together they usually share something: a fuse, a relay, a splice, or most often a ground point. We pull the diagram and look for what the two circuits have in common, then test that shared piece first. A single corroded ground bolt explaining both faults is one of the more common outcomes.
Can you do this on a work truck with added wiring in it?
That is a lot of what we see. Light bars, inverters, radios, lift gates, beacons and upfitter switches get added over years by different hands, often tapped into whatever wire was handy. Those added circuits are frequently the cause, and they are rarely on any diagram. We trace them physically, repair what was done badly, and fuse anything that was never fused.
Do you come to the vehicle or does it have to be brought in?
We come to it. That is the whole shape of this business, and electrical work suits it because the tools fit in a truck. Driveways, work yards, jobsites, shipper lots and the shoulder are all normal places for us to be, anywhere from American Canyon out through Napa, Solano and the wider Bay Area.
Stop buying parts and find the fault.
Tell us what quits, how often, and what else is going on when it does. That conversation usually shortens the job before anyone drives anywhere, and you will have a number and a window before you hang up. One phone number, answered around the clock, by the man who does the work.
HoursMonday to Sunday, 24 hours
Based inAmerican Canyon, CA
Related workWiring repair · Battery testing · Contact