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Can you find a single circuit that doesn't get power off of the TIPM in some way? Interior fuse box? Where does that fuse box get power from?
Starter Motor power doesn't run through the TIPM, it's a heavy cable direct from the battery for the motor positive cable and the ground circuit is through batt-chassis & motor-chassis cabling.
The OP reported a starter motor cranking problem somewhat improved by replacing the starter with a rebuilt unit. A not too uncommon source of the balky cranking problem reported is the heavy cabling and grounds. It would have been instructive to have done a number of starter draw tests to determine the voltage and amperage draw on the system by that starter AND a voltage drop test on the positive cable at the starter AND a voltage drop test on the batt-chassis and chassis-engine ground circuits.
The #1 common source of electrical power grounding for all of the systems in the vehicle is the batt-chassis ground circuit. As well, the #1 starting point for any of the power consumers, whether they get their power through the TIPM or through another fused circuit from the battery ... is the battery. That's why it's vital to verify that the power supply to the vehicle is capable of delivering correct voltage while maintaining amperage delivery to the systems under investigation. For true readings, it's essential that the power circuits be tested under load which stresses the high resistance and intermittent connections in the circuits.
Thank You for again making my point about starting the diagnostic process at the beginning and not in the middle of the circuits. "that fuse box" gets it's positive polarity power from the battery plus terminal through the cables and all of the power consumer circuits end at the battery negative grounding terminal. If the battery and/or the ground circuits are compromised, then every downstream electrical system consumer is compromised, be it computer, switch, relay, or power consuming item ... be it a light bulb, electric motor, solenoid, computer sensor system, engine ECU, fuel pump, interior light, instrument cluster & gauges, etc.
Some of these items will have a greater tolerance for out-of-spec voltage and higher than normal spec'd amperage draw, and will appear to function "normally". Others may not, and some will function intermittently.
PS: isolated and random high resistant grounds on various components in the world of computerized vehicles can cause feedback loops which may have random results on unrelated systems; ie, I've seen vehicles that ran perfectly until a high power draw day stressed the main battery ground circuit, such as turning on wipers/climate control system/headlights ... and then the vehicle didn't always shift properly, or maybe had a "flat spot" at tipping in the throttle just off idle, or an instrument cluster gauge giving a different reading than "normal" under similar load/driving conditions. Overall, these types of problems are oft-times difficult to replicate because the causation is intermittent. That's why I'm such a stickler for starting to track down these problems from the beginning of the power supply system ... can't tell you how many MB CU's ($$$$) I've seen replaced at dealerships because of an engine performance complaint and yet the vehicle persisted in delivering intermittent various engine response which I "cured" by repairing the main batt-chassis ground circuits. Or a host of other running or accessory problems that were seemingly random and unrelated ... stuff as simple as poor brake-light grounds leading to an engine performance problem when the driver stepped on the brakes ... sometimes, but not always. I've had the opportunity to work on many "restored" cars that were insurance wrecks or flood damaged cars, and most body shop workers aren't too particular about stuff working properly after the car is assembled ... circuits such as taillamp ground wires have been a frequently seen problem; the B-shop guys turn on the lights and any indication of a bulb illuminating is OK by them ... and a poorly grounded lamp may light up but not correctly and when the car is on the road, intermittently.
When you look at the schematic for this vehicle, a "bad" (ie, intermittent) ignition switch would have many components shut down when the switch open circuited. Easy stuff to notice, such as no ignition, no fuel pump, lights, climate control system ... it'd be hard not to notice the hiccup in the engine running or lights flashing or a blower motor slowing down airflow for that moment.
Still no resolution. I tried to take it back to the shop today to give them a chance to fix it, but they were too busy. Someone did not show up for work. Trey said they lost people to the boosted unemployment checks and believe they will be better able to handle the workload when the boost ends and people go back to work.
So new issue that seat belt light comes on and chimes repeatedly and randomly. Even though everyone is buckled. Frankly that is the most annoying thing from a drivability standpoint. Otherwise it runs/drives fine.
The starter things is weird. It is not slow to crank and when it finally starts it starts right up. What happens when I turn the key sometimes is nothing. Then the starter engages, but just for a second and stops, then nothing, then it engaged for a second and a half and stops, then nothing, then it engages for two seconds and stops. Eventually it engages long enough to start. Sometimes it just starts right up. When it is acting up, it seems like each crank gets progressively longer and so does the time between pulses of power to the starter.
People I demonstrated this to said they have never seen anything like it. I cannot find anything on the internet either.
I made an appointment for them to look at it next Saturday. Hopefully they will find an answer. There is only one good auto electric tech around that i know of and he is booked for over a month. The dealership has one, but they share him with two other dealerships and he is really not all that good. Either a serious shortage of automotive electricians or I am just no looking in the right places.
I really is not a major problem except I am concerned that one day it will just not start at all. Plus I do not love having all the lights flashing and chiming.
On the plus side, the new starter was free. Turns out the one I had in there was a Duralast Gold (lifetime warranty) and the replacement was the same thing, so they gave me my money back.
Coldjensens ... the problem as you described it in your first post and the fact that replacing the starter did not affect the problem points to the power supply problem that I’ve been posting all along in this thread.
I have seen this identical problem numerous times over the years.
What typically happens is power cables/connectors/grounds from the battery to the starter have failed.
When you turn the key to the “start†position, the starter solenoid commands the power to flow to the starter motor. But due to the high resistance connection, the voltage drops and the current delivered is less than can turn the starter motor. But the starter motor is still on line and demanding current. Very quickly, the high resistance connection heats up and “arc welds†itself partially back together ... now creating a lower resistance connection and the proper current flows to the starter motor, so now the starter motor spins. But the weak welded connection fails under the load of the current and quickly opens up again to a high resistant connection that cannot deliver the voltage and current needed to spin the starter motor. This cycle repeats itself pretty quickly, which is why the starter motor spins for a second or so, then stops, then starts again, and so forth.
The engine finally starts on one of those cycles where the starter has spun the crankshaft long enough to get a cylinder through a compression/firing cycle fast enough that the combustion starts and that first cylinder is the one that pushes the crankshaft rotation fast enough that the next and subsequent cylinders are running ... engine started. In this scenario, it’s very likely that the starter motor has quit turning again but that is masked by the desired result of the engine “startingâ€.
While I have seen failed battery cable connectors and internally failed cables (the inside wires have turned to a crystallized state, usually from overheating due to higher current loads than the cable was rated for) on the positive and negative cables, these are less frequently seen failures.
The most common failure I’ve seen to create this problem is the Grounding circuits from the battery-engine, battery-chassis, battery-starter.
The other electrical system random failures are related in that they indicate a poor power circuit. As I have repeatedly explained in this thread, it’s worthwhile to diagnose this vehicle at the beginning of the electrical power system ... the battery positive and negative circuits. Intermittent clean power to these accessory electrical consumers drives them “crazyâ€. Some of the symptoms you’re seeing are because the system keeps interpreting the interrupted power as cycling the system on and off.
My focus on starting the electrical fault diagnosis in this area of the truck is because the circuits involved are the ones that have the electrical power to: 1) do this weld-break connection- weld cycle, and 2) have the cables/connections that are sizable enough to repeatedly do the cycle; ie, there’s enough conductive material there to do this. By way of comparison, smaller/lighter amperage circuits in the vehicle, if they have that initial high resistance connection, typically fail and don’t have enough power or material to do the “weld†cycling; IOW, if a given circuit fails for a small power consumer, it will typically remain failed and that item won’t work at all. Key, also, in the diagnostics here is that the starter solenoid has consistently commanded the starter motor to spin every time you’ve gone to start the truck while the starter motor intermittent run cycle has been persistent ... and, at this point, other critical systems such as the fuel pump and ignition system apparently have always performed when commanded to do so. If, OTOH, you’d reported that the engine failed to start or had running problems once started, then we might point to a power distribution box failure.
Looking forward to your update from the shop and I hope they can readily isolate and repair your vehicle.
PS: just for reference, the accepted standard for resistance in high current draw automotive connections is .2v drop per connection under load. If a voltage drop across the ground or power cables to the starter is higher than that, you’ve found a problem area.
PPS: upon further reflection, it dawns on me that the cranking symptom is consistent every time you go to start the engine. It follows that a simple way to eliminate the key start/ignition switch side of the system would be to use a remote starter switch on the starter to command it to operate. If the starter still has the intermittent cranking symptom, then we’ve eliminated the ignition switch/key start circuits as the cause of the failure.
I took it back to the repair shop and they said the problem is not related to anything they did (of course). Then they said it was probably from the replacement of the heater core a year ago by a different mechanic. They seemed to think it much more likely the problem was created by someone else and gradually manifested over a year long period and finally happened by chance to show up the same day they did their work.
I do not think I will be going back there. Too bad, I was happy to find a mechanic who is open on Saturday.
Odd thing is when I got it back, the air bag light, the seat belt light and the check engine light were no longer on, although the other problems continue.
Next step - get in line for an appointment with the auto electric specialist
Well now it is only ESP BAS and traction light on. The air bag light and seat belt light come on, but very rarely and then they go off again. The last four or five starts, it started normally. I cannot take it to an electrical place f it will not do the thing I am taking it there for. I will give it some time and see what happens. there is a process to clear the ESP BAs code that i will try.
Could it be related to warmer weather? It seemed to go away as soon as it turned super cold again. That does not make a lot of sense, but electrical issues can be quirky.
Maybe the repair shop that caused it, partially fixed it by mistake. Or maybe they knowingly partially fixed it and lied about it because they did not want to admit causing it.
Anyway, now all I can do is give it some time and see what happens.
Well now it is only ESP BAS and traction light on. The air bag light and seat belt light come on, but very rarely and then they go off again. The last four or five starts, it started normally.
These types of intermittent failures generally don't fix themselves.
Perhaps the shop did take a cable or connection apart and tighten, or clean it up?
I cannot take it to an electrical place f it will not do the thing I am taking it there for. I will give it some time and see what happens.
Intermittent electrical faults, by their very nature, can oft-times be difficult to replicate at the shop.
That's why I advocate doing voltage drop tests under load of the major wiring areas that typically have a high failure rate for the types of problems you're experiencing.
there is a process to clear the ESP BAs code that i will try.
Could it be related to warmer weather? It seemed to go away as soon as it turned super cold again. That does not make a lot of sense, but electrical issues can be quirky.
Ambient temps can certainly play a part in these types of electrical faults.
"quirky" ... only because they're "hidden from view" as opposed to seeing failed hard mechanical parts, or obvious fluid leaks, etc. Electrical issues can't be readily seen, it takes knowing how to use the equipment that shows what's going on in that invisible realm ... a voltmeter, an oscilloscope, and an ammeter. For a tech that knows how to use these items, electrical system faults ... especially "high power" (such as an intermittent starter draw) faults ... are no more difficult to find than a visual inspection of broken engine parts.
Maybe the repair shop that caused it, partially fixed it by mistake. Or maybe they knowingly partially fixed it and lied about it because they did not want to admit causing it.
Customer education and good communications are paramount to establishing and maintaining trust for a shop. Sounds like you're not getting either from this repair shop and that alone is cause to seek other solutions ... if for no better reason than this shop doesn't appear to be getting the results you require. While they may have done good work for you in other areas, it does sound like they're out of their depth when it comes to electrical items.
Anyway, now all I can do is give it some time and see what happens.
IMO, it would still be beneficial to take the truck to an experienced/knowledgeable automotive electrical/electronics shop and give them the opportunity to check the vehicle out. With a logical, consistent, and willing approach to investigate, diagnose, isolate, and repair likely fault areas in your truck, they may be able to effect a proper repair even if a symptom fault is not readily apparent to you.
My biggest concern is the same as you expressed in a prior post ... the potential for the intermittent starter failure to strand you somewhere in your travels.
PS: It's probably very likely that the shop is correct that "nothing they did caused these problems". But here's where they and I differ ... from your narrative, it sounds like they're very defensive about their performance rather than getting to the bottom of the problem(s). In my shop, I'd be aggressively seeking to find out what was causing the problems, durably repair it, and show you whatever documentation I could to explain what happened to the vehicle and what I did to fix it, usually by showing you any failed components (and you're welcome to take them home, they're all yours) and/or photographs (digital snapshots are a no-brainer).
Whoo Hoo. I finally got it in to the local electrical shop today. For that place, getting in in only a month is lucky. Now at least I should be able to find out what it is.
Turns out the fuse box and attached computer module was fried. It is discontinued but they found a used one for $500. Then they found the 4x4 module was shorted out. They do not know whether the 4x4 short caused the fuse box/computer problem or the other way around. I think it is likely the former. I occasionally had a problem when I went through a car wash where the truck would get stuck in 4x4 low and would not change. After letting it dry out for a day, I had to go through a complex reset procedure and then it was fine again. Also another mechanic found some sort of 4x4 controller was full of algae (probably water got in from car washes) he cleaned it out and put in some dielectric grease or something like that to prevent water from causing a problem as much as possible (I should have had him replace it, but could not afford it at the time it might have saved me $500 if I had). These two fixes solved all the problems except the speedometer jumping around on occasion. They could not find the cause of that. It does not bother me, I just hope it is not another developing electrical problem. Total cost was $880. Seems reasonable if they had to buy the used fuse box for $500. Of course they must have marked up the fuse box since it took them a couple of days to find one. They need to get paid for their time finding it.
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