2007 Chevrolet Silverado Classic Electrical Problems

Well, since the newfangled web forum I posted to hasn't exactly bristling with answers, especially helpful ones, I figured the old tricks were the best and so I have returned. (Amazingly my ISP still has a running news server.)

I traded my 2003 Chevrolet S10 for a 2007 Silverado Classic (carryover body style) LT 4X4 pickup truck when the S10 dropped its fuel pump. I decided it had simply fallen apart beyond what I was willing to fix. Everything's been going well with the "new" truck, or rather, it was until a few days ago.

The trouble started when the Engine Hours counter in the DIC display reset itself to zero. There's no way to do this manually per the owner's manual, but nothing else was affected at the time. A half hour later, the ABS and Brake Fault lights came on, complete with lots of warning chimes. Not long after this I discovered that the blower fan did not function on any of the first four speeds. The fifth and highest blower speed works fine. All others will provoke the brake system warning lights and chimes at random. They'll also cause the cruise control to lose its speed memory when engaged. It then has to be reset.

No fuses are blown. I tried replacing the blower resistor pack to no improvement, thinking it might be an issue with the spike suppression diodes on that assembly. There is no burned wiring at the climate control head (manual dual zone), resistor pack or blower motor. Ground at the resistor pack tests good (zero ohms resistance between it and unpainted body metal). Volt meter shows 11.5 volts at blower motor terminals with motor unplugged and meter connected when control is cycled through the first four positions. Meter shows 11.8 volts at the highest fan speed position. (Engine was not running during these tests.)

I can't imagine the blower motor itself is bad. I'd expect it to overheat, blow fuses or not get up to speed if it was bad. It doesn't have a lot of inertia when spun by hand, but I don't know if a "known good" fan motor would be different. There is no unusual noise from the blower assembly that would suggest a bad bearing.

I noticed yesterday upon shifting into four wheel drive mode (floor mounted shift setup) that the four wheel drive symbol in the instrument cluster did not light (despite the truck very clearly being in 4WD mode) and the ABS/brake failure lights once again came on.

This really seems to me like it should be a ground problem, but I sure haven't found a bad ground.

Any thoughts? Help would be greatly appreciated--driving around with the blower on high all the time is getting old!

William

Reply to
William R. Walsh
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Sure acts like a bad ground to me.........

Reply to
clare

Or worse, caught in a flood. Hope that is not the case. Ground would be much better a problem. Just difficult to fix.

May the force be with you.

Reply to
bilb2765

Grounds are actually the simplest problem to fix - after you find the problem. Get the wiring diagram. Find the ground wire on the instrument panel. Tap into it and acrew the wire to the body. Did it fix the problem? No? Look for another related ground and try again.

Bad connections on the power side, on the other hand , are a BITCH.

Reply to
clare

Wow.. that's one heck of a problem

Reply to
fft

On Thursday, October 31, 2013 5:21:50 AM UTC-4, William R. Walsh wrote:

with answers, especially helpful ones, I figured the old tricks were the b est and so I have returned. (Amazingly my ISP still has a running news serv er.) I traded my 2003 Chevrolet S10 for a 2007 Silverado Classic (carryover body style) LT 4X4 pickup truck when the S10 dropped its fuel pump. I deci ded it had simply fallen apart beyond what I was willing to fix. Everything 's been going well with the "new" truck, or rather, it was until a few days ago. The trouble started when the Engine Hours counter in the DIC display reset itself to zero. There's no way to do this manually per the owner's ma nual, but nothing else was affected at the time. A half hour later, the ABS and Brake Fault lights came on, complete with lots of warning chimes. Not long after this I discovered that the blower fan did not function on any of the first four speeds. The fifth and highest blower speed works fine. All others will provoke the brake system warning lights and chimes at random. T hey'll also cause the cruise control to lose its speed memory when engaged. It then has to be reset. No fuses are blown. I tried replacing the blower resistor pack to no improvement, thinking it might be an issue with the spi ke suppression diodes on that assembly. There is no burned wiring at the cl imate control head (manual dual zone), resistor pack or blower motor. Groun d at the resistor pack tests good (zero ohms resistance between it and unpa inted body metal). Volt meter shows 11.5 volts at blower motor terminals wi th motor unplugged and meter connected when control is cycled through the f irst four positions. Meter shows 11.8 volts at the highest fan speed positi on. (Engine was not running during these tests.) I can't imagine the blower motor itself is bad. I'd expect it to overheat, blow fuses or not get up t o speed if it was bad. It doesn't have a lot of inertia when spun by hand, but I don't know if a "known good" fan motor would be different. There is n o unusual noise from the blower assembly that would suggest a bad bearing. I noticed yesterday upon shifting into four wheel drive mode (floor mounted shift setup) that the four wheel drive symbol in the instrument cluster di d not light (despite the truck very clearly being in 4WD mode) and the ABS/ brake failure lights once again came on. This really seems to me like it sh ould be a ground problem, but I sure haven't found a bad ground. Any though ts? Help would be greatly appreciated--driving around with the blower on hi gh all the time is getting old! William

The problem is not in the main battery cables since the engines spins good when it starts. The problem is in the secondary electricial (acessorises) s ystem that feeds the PDC (fuse block under hood). The cable that feeds the fuse block comes from the 175amp fuse that is on the firewall next to the b attery. The positive cable feeds this and the starter. A bad connection her e will cause the dood locks to cycle and all acessories including the headl amps to go dead. The problem is in the connection under the fuse block. The red power wire is connected to the box when the fuse block is locked in th e retaining box. It has a knife edge that inserts into the connector when t he box is locked. Inside the connector is a double wedge insert that tighte ns around the knife edge when installing. Problem is the insert folds under the edge causing a poor connection. The hotter the weather and the high us e of electrical compontants will triger an overload on this connector. Sinc e it is hid, you can't feel the extra heat on the connector. Checking a vol tage drop from the cable to the fused block will verify the problem Remove the fuse block and the cable with the end. Remove the cover off the end and the lookm closely at the insert. It should look the same on both sides. On ce you remove the insert, the problem in obvious. I have worked on three of these trucks and fixed all three with a new cable. Be careful when you ins tall the fuse block on the new cable. It should lock easy. You can repeat t he same problem if not careful.Good luck!

Reply to
lcmcraft33

I have a 2005 Silverado no crank no start I change starter checked all fuse s and relays nothing has worked gear indicator light is out reverse light d oes not come on when you try to start it the throttle body clicks the relay s in the fuse panel under the hood click but will not engage the starter wh en trying to jump the new starter with a screwdriver it has power it tries to engage I have change the starter I have changed relays or fuses are good I don't know what to do at this point anybody out there also the check eng ine light is not illuminated at all on my instrument cluster not when key t urned forward it does not display any more like it magically disappeared

Reply to
strictlybusinessss6

Take it to a dealer. You have already spent more that it would have cost to have the problem diagnosed (and likely fixed). My suspiacion would be the gearshift postion sensor but do NOT just jump in and change it without having it properly checked. You could replace every bolt-on part between the front and rear bumper without finding the problem

Reply to
clare

Do I need to unplug everything to get at it or is there another way to disconnect ,looks like a lot to take off,,cAbles are very tight

Reply to
pdferguson44

Also when I do a drop test, when I remove two fuse that are pulling Amps I still show .86of a amp no other fuses show a drop ,but she's still pull pulling current ,could this b e the positive cable off the mega doing this in the fuse block as well...

Reply to
pdferguson44

When I did my drop test I found the radio and the on star fuse pulling 3/12 amps no other fuses are pulling Amps but there is about.85amps showing to be drowning could this be do to the connection of the mega fuse cable being a bad connection under the fuse block....done a lot to importers not much working ,I could use some help ...my name is Paul

Reply to
pdferguson44

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