I recently went in to a repair shop to see if they could do an easy fix for my backup lights that went out. The bulbs were good and they couldn’t find anything loose. They told me they would have to run an electrical trace on it. They then told me that my CV boot (outer) needed replacing because it was ripped. I want to know how these mechanics started troubleshooting internal wiring for the backup lights and ended up poking underneath the car and “discovering” a ripped CV boot. They said it is more cost effective to just replace the 1/2 shaft vs. just the boot because of the labor. I was quoted $179 (San Diego, CA). Is there a logical explanation for “discovering” a ripped CV boot while troubleshooting internal wiring or should I suspect foul play so they could drum up business? Needless to say, I didn’t get the backup light fixed nor CV boot replaced…yet. I checked myself and the boot itself isn’t ripped but the aluminum clamp attaching it to the thingamabobber is detached. Regardless, I will have to get it replaced but want to know if I should suspect this particular auto shop of foul play.
Is there a logical explanation for “discovering” a ripped CV boot while troubleshooting internal wiring?
Well, the shop has a vested interest in fixing stuff on your car, and you have a vested interest in getting things like bad CV boots/joints before they fail in use. Considering those common interests it is reasonable (and ethical) that the shop gave your car a “visual once-over” when you brought it in. (A torn, leaking CV boot would be easily apparent via visual inspetion.)
…or should I suspect foul play so they could drum up business?
Absent some other cause for suspicion, absolutely not. Could they have sabotaged your car to produce a bad CV boot? Yes, but if you have to worry about sabotage with your mechanic, the relationship (rightly or wrongly) is poisoned already.
My only suggestion is–if the boot is intact, the CV joint still somewhat greased, and no “clicking” while turning–you might be better served re-greasing, refastening, and hoping you caught it in time.
If the clamp has been loose, it may have allowed contamination of the join and it may be best to at least examine it, clean it and reattach it. Just re-attaching it is a bit iffy.
It’s not all internal wiring. The backup light switch is located on the transmission, which is UNDER the car. They had to raise the car to check the switch, or at least they should have. While the car is raised it’s easy to spot a loose or torn CV joint boot.
Anyone who can’t fix the backup lights should not be trusted with anything more complicated. Find another shop.
I don’t see anything suspicious here at all. From your post I gather they have not charged you one dime up to this point or done any diagnosis because you were just looking for a quick opinion without spending any money.
Odds are the switch is the problem but if a mechanic is going to spend time checking and verifying the problem he should be paid for it. Otherwise he is spending time for free since he works on a commission basis.
It’s also very common and very easy for a tech to spot or be aware of other problems on a car and bring it to a customer’s attention as the vast majority of cars on the road are neglected. Case in point, the CV boot which you were not aware of.
If the boot has been torn or the clamp has been off for a while odds are the CV joint may fail sometime in the future as dirt and water has been admitted to the joint and contaminated the grease, or what grease is left.
I too find nothing suspicious.
When you checked the boot yourself, did you check between the folds? Thst’s where they typically fail.
They’re right about replacing the half shaft. It would need to be removed to replace the boot anyway.
Just as a suggestion, in future when you bring a car to a shop and the tell you XXX needs toe be fixed, ask them to show you. Any reputable shop will be happy to. Any that won’t doesn;t deserve your business.
It sounds like you’re trying to lecture me (“vested interest” and “poisoned relationship”) when I was looking for an answer about how a mechanic got from point A (looking at internal wiring) to point B (underneath the car). Your reply was not helpful at all but thanks for trying.
Yea, I’ll take care of that. That’s not an answer I was looking for though. Thanks anyway.
Under the car? Oh, ok. I see how the mechanic would have noticed the detached CV boot if they had to lift the car. I had no idea a backup light switch would be under the car. Strange place for switch… So it’s on the transmission, even on a manual trans? So you’re also saying that the mechanic should have been able to fix the backup light? He said they checked all the wiring and the next step was to put my car on a electrical trace (or whatever that test is called).
Nah, it was a courtesy check. I’ve done some work with them before. Not all mechanics work on commission. These guys don’t (at least that’s what the manager told me).
“It’s also very common and very easy for a tech to spot or be aware of other problems on a car and bring it to a customer’s attention as the vast majority of cars on the road are neglected.” Not too common when a mechanic is working on internal wiring to just take it upon himself to put the car on a lift to see what’s going on underneath. Or so I thought. Mcparadise (above) answered my question about how a mechanic goes from checking internal wiring to seeing a detached CV boot (since the car would have to be on a lift in order to see it).
LOL! I’m not going to put my hands in that goop! I just peeked underneath and it was obviously detached. No further investigation required. 
Yea, I will get the half-shaft replaced. Might as well… A supervisor showed me the CV boot failure by sticking his finger behind the tire and it came out with goop all over it. I’m just naturally suspicious of mechanics. Thanks for the reply.
It’s not the mechanics who have the problem…Your ignorance about cars leaves you a sitting duck for all kinds of scams…You probably consider yourself to be highly educated, but in fact, you are not…