- This topic has 56 replies, 10 voices, and was last updated 10 years, 3 months ago by
.
-
Topic
-
Being able to understand wiring diagrams and troubleshoot wiring often separates the men from the boys (or, not dissing the ladies, the “real mechanics from the wannabes”). So, I confess, I’m a boy on this one. The vehicle is an ’02 Chevy Venture LS with front wheel drive 3.4L engine.
Coolant fan number 2 (passenger side facing vehicle) stopped working. With our hot Southern summers and a salvage yard nearby, I went and bought another fan without attempting any diagnostics. I discovered the issue is not the fan. Number 2 cooling fan will not come on. Here is what I know:
The cooling fan (salvage and original are good) This was determined by testing fans off the car, and using the connector for cooling fan 1.
I checked the fan wiring harness for continuity (pictured at bottom), all is good.With my multimeter, I verified I have good current going to the motor (light blue wire) and coming from the motor, black.
Both relays are fine, I swapped them.
Both 30 amp maxi fuses are fine.
The ac clutch relay seems to work, it turns on the number 1 fan when ac is turned on.
My tests were performed with the vehicle cranked and the ac turned on…I’ve used a bypass wire from coolant fan number 2 black at the fan and grounded it. Still the fan will not work. I’m scratching me head here. With proper voltage going to the fan and grounding the return it still will not turn on.
I’ve attached a few photos, including a wiring diagram. Maybe you can see it without it being too blurry. Please be gentle if I’ve colored something wrong. Staying dirty and learning.
-
Replies
-
I wonder what was the root cause of this failure…
Possibly unwanted resistance in a high-amperage circuit..?
Furthermore, why only this connection affected? Perhaps surrounding connections could also be compromised (possibly due to environmental exposure?) but do not exhibit the aforementioned failure because of low current draw. I believe in the cases, it would be more likely that the affected circuit would demonstrate an ‘open’ as opposed to a current deficiency (not enough juice to burn stuff.)
Q: what type of wire repair are you planning… will soldering be an option?
I think one possibility could be to terminate the wire with a new connector and install the connector into a free and undamaged adjacent space in the fuse box.
Anything is possible.
I see this quite a bit on high draw circuits on the games I work with. The connection itself is the weakest link in the chain. Start getting a bit of oxidation..starts to overheat the connection–gets higher resistance…..more oxidation and burning..
And then the connection is toasted so it can’t do it’s job. The telltale sign is how the wire is discolored. You can see the heat pattern, kinda like how a fire investigator does his job. The origin point will be the toasted spot..radiating outwards with less and less heat damage.
There might be more at issue here that needs to be checked. If the fan in question is drawing to much current? (Which would be resolved–as the gentleman already changed out the fan for a different one–The damage was already done…)
How to fix that is another issue. I know how I would address it–With an external socket and a whole lotta careful soldering and remounting the relay. However that might be overkill. Looking forward to seeing how this gets addressed, as I tend to go overboard with my repairs with over thinking it.
S-
edit: There may also be other problems..don’t want to get anyone’s hopes up LOL. But that repair would be a great place to address this issue!!
I’ll document my attempted repair. The adjacent fuse fuse panel space is a great idea Ratchet Face. If there’s room, I’ll consider that. I agree with Teddybear315’s idea that over time the connection became loose/ overheated. Yes, the fan has been switched out, so if that was a contributing factor, hopefully it won’t be in the future. I’m not the greatest electrician, so hopefully my repair idea/ attempt won’t be a disappointment to you guys. 🙂
Back in the late 70’s to early 80’s GM operated the heater fan with the normal resistor block with one exception – high speed was powered by a wire off of the back of the alternator. When high speed failed, and it always did, you looked for a connector in a thick wire on top of the engine. It would be found in a plug with other wires crispy or worse. Sometimes the entire plug would get hot enough to distort. So, repair until the next time. I’ve fixed this more than once on the same car.
Trying to figure this out the first time is how I learned that 12 volts at the motor does not equal power.
Well, here it is fellas. We can call it fixed. After going to a couple auto parts stores this morning, I could not find any connectors like the one on the blue wire. Fortunately, I live relatively close to a Pull a Part auto salvage yard. That was my fix. I used the donor wire with clip and adjoined it to a butt splice with heat shrink insulation. I also used the donor plastic connector housing. It was a bit tedious to pop all those wires loose and transfer them. Using my pick, I tightened all the female ends as I transferred each wire. So far, so good. Both fan are now working. The half speed contro is working too. The AC feels better as well. I’ll keep my fingers crossed that this doesn’t happen again. Herd are some pics below.
Well, here it is fellas. We can call it fixed. After going to a couple auto parts stores this morning, I could not find any connectors like the one on the blue wire. Fortunately, I live relatively close to a Pull a Part auto salvage yard. That was my fix. I used the donor wire with clip and adjoined it to a butt splice with heat shrink insulation. I also used the donor plastic connector housing. It was a bit tedious to pop all those wires loose and transfer them. Using my pick, I tightened all the female ends as I transferred each wire. So far, so good. Both fan are now working. The half speed contro is working too. The AC feels better as well. I’ll keep my fingers crossed that this doesn’t happen again. Herd are some pics below.
Well, here it is fellas. We can call it fixed. After going to a couple auto parts stores this morning, I could not find any connectors like the one on the blue wire. Fortunately, I live relatively close to a Pull a Part auto salvage yard. That was my fix. I used the donor wire with clip and adjoined it to a butt splice with heat shrink insulation. I also used the donor plastic connector housing. It was a bit tedious to pop all those wires loose and transfer them. Using my pick, I tightened all the female ends as I transferred each wire. So far, so good. Both fan are now working. The half speed contro is working too. The AC feels better as well. I’ll keep my fingers crossed that this doesn’t happen again. Herd are some pics below.
Well, here it is fellas. We can call it fixed. After going to a couple auto parts stores this morning, I could not find any connectors like the one on the blue wire. Fortunately, I live relatively close to a Pull a Part auto salvage yard. That was my fix. I used the donor wire with clip and adjoined it to a butt splice with heat shrink insulation. I also used the donor plastic connector housing. It was a bit tedious to pop all those wires loose and transfer them. Using my pick, I tightened all the female ends as I transferred each wire. So far, so good. Both fan are now working. The half speed contro is working too. The AC feels better as well. I’ll keep my fingers crossed that this doesn’t happen again. Herd are some pics below.
- You must be logged in to reply to this topic.