@William K. I agree with your assesment of dealer mechanics as a rule, but I think this applies to other automechanics as well. I have used dozens of garages in the last ten years and have found that if the computer feed does not tell them what the problem is, they are totally lost. Sometimes they can figure it, but other times no. But that is not unique to automobiles. It extends to home appliances and office equipment as well.
Incompetance extend to many disciplines these days. I have a brown spot on my leg that the surgeon swore he removed. "What is that?" "It's gone." Even though we could both clearly see the spot the doc kept telling me it was gone. A section of tile replaced with uneven grout joints and that area of the floor is uneven. Maybe the edge of the lawn gets trimmed and maybe not. I really love the service people who work by complaint. "Hey. You missed a spot, or you forgot the other side of the yard."
I got into an arguement with a pest control service when I told them not to return. The office told me I had a contract and could not discontinue service. I told them they had voided the contract by doing shoddy work and I would no longer do business with people who only did a complete job in response to complaints. At least the mechanic at a dealer has some sort of factory training.
Helms prints the shop manuals, if they are available. I would check them out for a shop manual if you plan on keeping the truck. At least then you will have something to help learn how to trouble shoot the truck. $150 parts store OBD code reading devices are very vague.
Loadster, I have done a fair amount of successful troubleshooting from just this kind of distance on a number of occasions. It has saved me from a service call to someplace in the far northern realms of Canada in a February. That was a cold trip I was happy to avoid. Besides, remote diagnostics is an interesting game, it can be played as a real game if one team has the results of a good FMEA, and the other side is familiar with a design. Probably not a Parker Brothers best seller, but how many party type board games are made for engineers?
But your previous post appeared to me to be linking a lamp failure to an overvoltage caused by a poor ground, which is why the comment about circuit theory. I may not have perceived your meaning correctly, if so, apologies.
william k. I'll take your advice on circuit theory for what its worth. I was speaking to the possibility that the cruise control had lost its normally available return path to chassis ground and was parasitically referenced to the brake light return. Not that there was corrosion on the bulb connection though that is a more common scenario. This is all just spherical tuba lube, trying to troubleshoot and recommend from virtual, intangible perpsective.
Loadster, you need to seriously review basic circuit theory, concerning tha light burnout problem. Only in certain areas of the charging system can corrosion and the resultant high resistance cause an excess voltage, which would lead to excessive lamp current.
But a failure of a lamp to light because of corrosion would look like a burned out bulb, but it would instead be a poor connection preventing illumination. And so those unable to test a lightbulb to see if it has failed, no hope of effecting a repair by means of replacing a good bulb. The fact is that in order to produce an effective repair one must know what the problem is. Otherwise one is simply shooting randomly in hopes of hitting the right target. And you should be aware that sometimes those very inferior lamp bulbs made in China only last a few hours.
Aside from the brake switch, some cruise control systems include a dump valve that's attached to the brake pedal. When you step on the brake the valve opens the vacuum in the cruise control servo which release the accelerator and serves as a mechanical system to shut down the cruise control.
Agreed; cruise must be overridden by brakes and if brakes aren't right, then cruise should be disabled. My question is whether the brake light burn-out means current is excessive because a ground is corroded on the cruise circuit. Whenever fuses or lights burn out, my discovery is not quashed until the reason is defendable. Unless the car has recently been driven thru a lake. On the separate issue of resetting "check engine" flags, one can buy a DBII diagnostic for $50 to $150 or try the battery disconnect and headlight discharge method. You run the risk of resetting all your "learned" PROM if your car does that. I discovered on a late model Volvo that you can reset the service counter and "service soon" light by simply holding down the trip odometer button when turn on the ignition. Kind of like holding down a special key sequence on hand-held electronics or computers when you cycle power. I like things simple. The new PHEV don't apply.
The cruise control has to be linked to the brakes somehow so that it would allow one to stop the car. It used to be that there was a separate normally closed switch along with the nornally open stoplight switch on cruise control cars. But then with adding a controller chip they decided that the brake light signal could be used, but it would need to verify that the brake light power feed was live in order to have the system be safe. So the problem could be in that area.
Monkeys don't own suburbans. But your brain is being sublet to one. If your brake lights opening breaks your cruise control, then your cruise control is somehow using the brake continuity as chassis ground, either DC or capacitive. I'd buy a chiltons or a haynes book with schematics and try and figure it out before it bites you somewhere in the wrong place at a dangerous time. Or you can keep that monkey riding in your brain housing group, and hope for a barrel of monkeys to pull you out. I own a 96 yukon so thanks for the insight if my cruise ever snaps.
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