Diagnostic Time Is An Hour Before Anything Else

Diagnostics post at $285 an hour with a one hour minimum. Owners push back on that number more than on anything else on the sheet, and the objection is always some version of paying to be told what is wrong. The comparison that makes it make sense is not the diagnostic hour set against nothing. It is the diagnostic hour set against the parts cannon, which is what happens when nobody measures. Replace the converter. Still dead. Replace the batteries. Still dead. Replace the transfer switch. Now it works, and three components were bought to correct one fault.

Run that arithmetic honestly and it is rarely close. House battery replacement opens at $500, an inverter and charger at $750, and transfer switch and shore power work at $285. Any two of those exceed an hour of measurement by a wide margin. The parts cannon also has a second cost that is worse than the money. Every component replaced without a reason is a component whose removal disturbed something adjacent, and on a coach where wiring runs through cabinetry and under floors, disturbance is exactly how one fault becomes two.

The hour buys measurement and a written result. On the electrical side that means voltage under load rather than at rest, current draw at the fault rather than at the panel, resistance across a run that is suspected, and a scan of anything carrying a control board. On a chassis it means a scan tool session and the codes it returns, stored and pending, with freeze frame data where the module keeps it. On a systems fault it means pressure, temperature and flow measured where they matter rather than inferred backwards from a symptom somebody described over the phone.

It also buys the negative results, which are the part owners undervalue. Knowing that the battery bank is healthy, the shore feed is clean and the converter is doing its job is not a wasted hour. It is three suspects eliminated with numbers attached, and those numbers go into the file. If the job later becomes an insurance conversation, or if a second opinion is wanted, that file travels with the vehicle. Diagnosis without a written record is a story. Diagnosis with one is evidence, and the difference shows the moment anybody disagrees.

Diagnostic time is credited against an authorised repair. In practice that means the hour appears on the invoice as a line and comes off again if the work it identified is approved and performed here. Where it is not credited is the case where an owner takes the written result and has the repair done somewhere else, which is a legitimate choice and one that some owners should make. The measurement was real work performed by a technician on a lift, the result belongs to the owner, and it is priced accordingly rather than absorbed.

The credit changes what the decision looks like from the owner's side. An owner authorising the repair is, in effect, not paying for diagnosis at all, because the hour folds into the job. An owner who walks away pays for one hour and leaves holding a document that will stop the next shop from starting over from nothing. Both outcomes are acceptable here. What the structure is designed to prevent is the third one, where a shop skips the measurement, guesses, is wrong, and the owner pays for the wrong guess in parts.

Two priced services get confused with each other constantly. An RV systems estimate covering slides, awnings, water, electrical or a generator is $150, credited against an authorised repair. That one is a survey. A technician works through the systems named, records condition, and writes what needs doing and roughly which band it falls into. It answers the question of what this coach needs, across the whole vehicle, at a level of detail sufficient to plan a season and set a budget against it.

An in depth diagnostic is one hour at the posted diagnostic rate and it answers a much narrower question much harder. It is for a single fault that has already resisted the obvious explanation. Choosing between them is easy once the difference is clear. If the question is what does this coach need, the systems estimate is the right product. If the question is why does this one circuit drop out on generator power and only when the air conditioning is running, that is an hour of measurement and nothing shorter will reach it. Collision work runs differently again: insurance walk-ins are welcome and we write the estimate.

The hour goes first, before parts are ordered and before a repair estimate is written, and the sequencing is most of why it works. A repair estimate written ahead of measurement is a list of guesses with prices attached, and the prices lend it an authority the guesses have not earned. Once an owner has approved a number, changing it becomes a conversation nobody enjoys, so quiet pressure builds on everybody involved to make the original guess true. Measuring first removes that pressure completely, because nothing has been promised to anyone yet.

There is one ordering exception on a coach and it is a large one. Water damage and delamination cannot be measured without teardown, and teardown is repair labour rather than diagnostic time. On those jobs the sequence runs intake assessment, then teardown authorised on its own, then an estimate written once the substrate is visible. Owners sometimes read that as a shop refusing to commit. It is closer to the opposite. A number written over a closed sidewall is not a commitment, it is a placeholder, and everybody in the trade knows it.

The last thing the hour does is set a boundary on what follows. A written result names the fault, names what was eliminated, and names what the repair requires. That turns the next conversation into a decision about scope rather than an argument about cause. On a coach where three systems interact, that boundary is worth more than the hour costs, because scope creep on an unmeasured job is the exact mechanism by which a modest repair becomes an open ended one.

Measurement is priced here because it is skilled labour on a lift with equipment attached, and unpriced skilled labour has to be recovered somewhere else. Shops that do not charge for diagnosis fund it out of the repairs that follow, which means the customers who authorise repairs are covering the diagnoses of the customers who do not. That is a transfer, and it is invisible to everybody in the transaction. Pricing it directly is the less comfortable option at the counter and the more honest one on the invoice.

The second reason is behavioural and worth stating even though it is unflattering to the trade. Diagnosis nobody is paying for is diagnosis that gets rushed. A technician who knows the clock is not running has every incentive to reach for the most likely answer in fifteen minutes rather than the correct answer in fifty. Paying for the hour is what makes the hour available. It is also why the minimum is a full hour rather than a fraction of one, because a fifteen minute diagnostic is a guess with a meter in its hand.

Plenty of faults do not need it, and selling an hour of measurement against a symptom with one plausible cause is bad practice. A roof vent fan that has stopped turning, a water heater that will not light on gas but works on electric, a step that has stopped extending: those have short lists, and a technician works through them inside the repair labour without a separate diagnostic line. The same holds when the failure is simply visible. Nobody needs a meter to find a shattered lens or a snapped cable.

The other case is economic rather than technical. On an older coach where the suspected repair is worth more than the coach, an hour spent confirming which expensive thing has failed is an hour spent buying bad news at retail. It is fair to say that before the hour is authorised, and we do. Sometimes the right advice is to sell the vehicle as it sits and skip the measurement entirely, and an owner who hears that from a shop that could have billed the hour has learned something useful about the shop.