Jump to content


Article: Thinking Outside the Box - Case Study on an 04 F150 cruise control

Recommended Posts

Thinking Outside the Box

An 04‘ Ford pickup came into the shop with a non-functioning cruise control system that had already spent some time at a couple of other shops. None seemed to give the customer any kind of answer as to why the cruise control wasn’t working. And, like many of these types of jobs I get in from those “other” shops, they all eventually come to the same conclusion as to what’s wrong with the vehicle. You know, the typical bail out answer for a problem they couldn’t solve. They’ll tell the customer, “It must be electrical”, and of course, they don’t do electrical. Seriously, what isn’t electrical these days?

A lot of times I find the term “It must be electrical” is just an excuse from these other shops to throw their hands up and send the customer down the street. They either don’t understand the diagnostic procedures or have already spent way too much time swapping parts and components hoping they’ll eventually run across a solution rather than actually diagnosing the symptoms.

I’m not one to shy away from some “electrical” problem. I’m more than a bit bull headed and stubborn enough to stick it out to the very end. Even if that means going to the extreme to diagnose a given problem. This one was no different. But, first things first, as always, verify the customer’s complaint. So, off on a test drive I go. Sure enough the cruise wouldn’t engage. There was no green indicator on the dash and no signs of any action taken by the PCM to engage the cruise. Now, it’s back to the shop and grab the scanner.

Codes were absolutely no help. No codes were stored and no history to see. Which, is probably where these other shops stop testing things and came up with their conclusion, “It must be electrical”. For me, codes are only step one of many to solve an electrically related problem. Let’s face it, codes are not the defining answer. Today’s cars have so many different methods of watching the various components involved with each system that it just makes sense to use the scanner as a tool to aide in diagnosing, and not just simply for reading codes. For this problem using the scanner to look at the PID’s (Parameter Identifications) was going to be more than a bit helpful.

As I’m sitting in the service bay watching every function involved with the cruise (according to the operation description), I did not see anything out of place or giving me incorrect readings. Everything from the emergency brake signal to the BOO (Brake On-Off) signal were correct. There didn’t seem to be anything standing out as the culprit, but there had to be something, something that everyone else has overlooked. Sitting in the service bay is not where the cruise control does its job. The vehicle has to be brought up to speed, before you can rule out if all the various components are actually working according to the manufacturer’s specifications. So, it’s back out on the road, but this time with the scanner installed. The safest method is to have a co-pilot watching the laptop screen. With the truck moving down the road there was only one item that didn’t act the same way it did when the car was stationary, and that’s the BOO signal. As we drove around the BOO stayed ON all the time. It never switched from ON to OFF when the brakes were applied.

It’s back to the shop to try this whole thing again. This time I left the engine running and watched the BOO signal. As I pushed the brake pedal down, the signal switched back and forth from OFF to ON just as it should. Now what in the world is going on? I know I saw a constant ON signal while we were driving, but it shows ON/OFF as we are sitting still. That’s when I reached over and dropped it into drive and allowed the truck to roll forward just a bit. Well what do ya know, the signal never switched anymore. But, in park it worked just fine. I tried the same thing over and over again, and every time I had the same results. It can’t be the brake switch, I’m not changing anything there. The only thing that’s changed is the gear selector. So it’s got to be something with that. Could it be the TR switch? (Transmission Range) Nope, it’s working perfectly. So, what else can it be?

I went back to the description and operation page of the service manual, but even after reading it a second time nothing seem to make sense as far as what I was seeing on the scanner. But, there was one thing I thought might be involved that the general description page didn’t mention anything about, and that’s the shift interlock switch. According to the wiring diagram there is a signal for BOO at the shift interlock, but only briefly mentioned as a possible cause of loss of BOO signal in one of the sub headings regarding the diagnostic procedures for testing the brake switch. Still confused, but willing to go with the “It must be electrical” as the primary cause of the problem, I decided to check further into the shift interlock switch. This time instead of driving it or spinning the roulette wheel of possible components, I’m going to pull the shift interlock and check it myself.

From the outside of the little box everything looked great, all the connection are solid and there were no signs of something that might have been spilled into the console. The circuit box was not glued together and could easily be taken apart, and I had a pretty good idea it had to have something to do with the BOO signal going awry, it seemed like the logical thing to do. After I opened up the box, all I could say was, “Holy cruise controls there’s the problem!” A transistor had a burnt terminal. Now I’m more than confident this is the problem, time to order one.

After installing the new shift interlock I took it down the road for a quick test drive. The green cruise indicator light came on, it accelerated, resumed and functioned just as it should. The shift interlock was definitely the problem. Of course, just to prove my hypothesis that it was the cause of the entire problem, I had to perform the same test I did earlier by placing it in and out of park and letting the truck roll forward while watching the laptop. The BOO signal was doing its thing. ON then OFF just as you’d expect it to do.

It’s not the first time I’ve run across a diagnostic situation where all the PID’s or information given wasn’t in plain English. Sometimes what you have to do is go that extra step and follow your instincts as to what you believe is the problem. I’m sure another sharp tech would have a completely different way of coming up with the same answer, but in this case, this is how I came up with it, and it worked. That’s what counts in the end. The customer is happy, I’m elated and you can be sure I’ll be watching out for the same kind of problems in the future, too.

Even though my diagnostics information didn’t have all the answers laid out with pinpoint accurate details the answers were still there. Ya just had to dig them out from between the pages of the diagnostic manual. As with a lot of today’s electronic mazes, you might find yourself having to solve a problem that wasn’t a problem just a few years earlier. I mean seriously, who would have thought a shift interlock would have something to do with the cruise control 20 years ago? Or for that matter that you could look at so many different sensors or components all at the same time on one tool.


At times it does seem like an uphill battle to keep up with all the changes in the modern mechanics field, but at the same time very gratifying when you overcome a problem that seemed impossible to solve. Sometimes, ya just gotta think outside the box or in this case… open it up and look inside.


Click here to view the article

  • Like 3

Share this post

Link to post
Share on other sites

  • Similar Forum Topics

    • Customer's buying their own parts

      Hey guys. I'm new to the forum and was looking for this subject but couldn't find it. Sorry If I'm posted something that's already been discussed. I own a brake shop in Austin, TX. We do anywhere from 10-20 brake jobs a day. We only do brakes so I don't know how much full service auto shops deal with this problem but... Customers are constantly calling in claiming they've bought the best parts or they want to provide their own parts because they've done research and know what is best. This drives me crazy. First of all they don't know whats best. Then after being told no they get offended and act like tons of shops allow this. What is the best way to handle these customers? Just send them away? I'll quote them a price using our parts and they act as though its a rip off. What shops are doing this for their customers? I feel like I'm letting jobs get away from me. Any experience with this?

      By Jonathan Ganther, in General Automotive Discussion

      • 78 replies
    • Shop Owners: You don’t have to answer every question for your employees

      As shop owners, we sometimes feel that we need to answer every question and handle every situation. While you need to be proficient as a business owner, you also need your employees to think for themselves.  Empower your people to solve problem.  Ask them for their opinions and don’t be too quick to jump in on every situation.  The more you jump in and solve their problems, the more they will rely on you. This is not to say you don’t have their back; but a team functions best when everyone takes ownership of their position and takes responsibility to take care of problems. Will employees make mistakes? Yes.  But there isn’t a shop owner on this planet that has a perfect record at making decisions.  We all make mistakes. As a shop owner; teach, mentor and coach.  Include your employees in on decisions that relate to their job position.  When employees feel you trust them, they will begin to solve their own problems. This will set you free to work on the things that will bring you greater success.

      By Joe Marconi, in Joe’s Business Tips For Shop Owners

      • 2 replies
    • Article: Defining Your Ideal Customer

      We all have our favorite customers. You know who there are. They’re the ones that throw their keys on the service counter in the morning and say, “Do what you need to do and I’ll see you at 5 p.m.” They never question your price, they trust you and they keep coming back. But does that person define your true profile customer? The answer is probably yes. But it’s not the only criteria. It’s a little more complicated than that. Defining your true profile customer starts with you. It starts with who you are, why you are in business and the culture of your company. By the way, determining your true profile customer has nothing to do with excluding certain people due to their income level. The young 23-year-old college graduate who sets aside part of her paycheck to shop at Whole Foods does so because she believes in the company and for what they stand. It’s not about what she “supposedly” can or cannot afford. She is Whole Foods’ profile customer because she aligns herself with that brand. And Whole Foods welcomes her with open arms. Many of my profile customers endured tough economic times during the Great Recession of 2008. They lost their ability to pay for some of the things they previously could afford. What they didn’t lose was their loyalty to my company. So, what did we do? We helped them through that difficult time. We helped them manage their car care needs better, offering services that would save on fuel, reduce repair costs, and reduce breakdowns. We showed them how to squeeze every mile out of their tires and brakes. We took care of them and we still do to this day. We consider them family and we don’t turn our backs on family. One thing we didn’t do, and will never do, is compromise on price to get a job. That would not be fair to all my customers, my employees or the company. With regard to pricing your services and repairs, it’s a delicate balance between being profitable and competitive. But I don’t know of any shop that prefers a customer walk away or sends someone to another shop because he or she cannot afford a particular price. A smart service advisor will give options, prioritize the work needed, and offer finance options. If you’re a startup company, your doors are wide open to everyone. You need customers and car counts, and you need them right away. But as your business matures, you begin to realize that not everyone is your customer. And there’s nothing wrong with this realization. As you build your customer base, you begin to see that there are customers that respect the work you do, align themselves with your culture and appreciate what you do for them and for the community. They become your profile customers. Let’s say you sponsor a youth baseball team in your area, help out at community events and involved with local fundraisers. You will become known as the business person that cares about the community and children. That’s making your business stand out among the rest. As you define who you are, you also attract those that want to do business with you and support your brand. While I do recommend treating everyone the same, I don’t recommend trying to be everything to everyone. That’s not a sound marketing strategy—that’s a recipe for failure. Defining your customer and targeting your market does not isolate consumers. It actually increases market share. Here’s an important fact: In your geographical area, automotive shops basically do the same thing; they repair and service automobiles. So, how is a consumer going to choose you over another? You need to stand out. You need to be different. You need to build a brand culture and establish a marketing position that will make people take notice. By the way, every successful company, large and small, understands its true profile customer and creates a marketing plan on attracting them. One last thing: When you build a business around your culture, you put the focus on your brand and the value you provide. This strategy is one of your pathways to success. When you combine value with culture, you will have an enduring and profitable company. If you want to build a great company, ask yourself these questions: Why are you in business? What’s your life’s purpose? Your culture? Build a marketing strategy and a brand message around the answers to these questions. Not all people will take notice, but your profile customers will.    This story was originally published by Joe Marconi in Ratchet+Wrench on August 3, 2018
      View full article

      By Joe Marconi, in AutoShopOwner Articles

      • 0 replies
    • Many aging Auto Shop Owners thinking about retirement

      Our industry has many shop owners well into their 60s and 70s, some even older.  For many, they have taken a secondary role and have handed the business off to a younger family member. For others, they know that there are more years behind them then in front of them and planning their exit plan or succession plan. A question for all the senior shop owners out there.  What are your plans for future?  Sell the business? Keep it in the family? Continue to work as long as your can?  Or something else?    

      By Joe Marconi, in Exit Strategy, Retirement, Selling Your Repair Shop

      • 1 reply
    • Customer Financing

      We want to start offering finance options to our customers. Can anyone recommend some companies that you use? I've heard good things about One Road Lending. GE Capital is now Synchrony and they have horrible reviews. Appreciate your help! Thanks, Pam

      By pam, in General Automotive Discussion

      • 17 replies
  • AutoShopOwner Sponsors