This fuse blows!... and so does HF!

[dazza]

First and foremost I'll address the latter of my title...
STAY AWAY from Harbor Freight blade fuses! For the past few days I've been dealing with my electric fan blowing fuses. When I first noticed my over-temp I found my 30 amp fuse between my battery and my fan relay had blown. This happened a second time on the next drive.

The third time, which was the first HF fuse I put in didn't blow!... no, the metal stayed intact but the plastic casing completely melted off into my fuse holder!
Spending yesterday troubleshooting the reason for the fuse popping, I took the opportunity to test the HF fuses with others I had and every one of the HF fuses melted without blowing, including a lower amperage (20A)!

In reality, I'm not surprised, and maybe myself and the one reviewer on their site happen to get a bad batch, but seems to me that's a company just asking for trouble.

In the end, I'm still having an issue if anybody can drop a little insight. Basically, when my temp sensor reaches the correct limit, the fuse pops. If I turn the truck off, replace the fuse, and then put it in the on or acc position without starting, the fan kicks in normally. So only when the truck is running. Here's a quick schematic of that circuit.

[Andy4639]

First question has it been working before and just started poping the fuses are has it never worked per the wiring schematic you posted.
Check the wiring to see if it has melted the wiring together.

This is how I like to wire them.
Try swapping 85 and 86 on the relay.

[dazza]

It was working fine, I'm just trying to remember what the hell I was messing with just prior to it's first blown fuse. I've been through all the direct, fan related wiring including a derale relay that says 86 should be ground and is rated 40/60A instead of just 30.

I'm wondering if a 30A fuse just isn't quite enough? Maybe I'll try a 30A self resetting circuit breaker I have.

[Andy4639]

I would try at least a 40 amp first.

[CaptRMW]

See if the fan spins freely. I had one 2 months ago that started popping fuses and one of the permanent magnets in the fan motor came unglued and was wedging against the armature. Another piece of Chinese crap up in smoke..

[BrianG]

do they still make slow blow fuses? Remember the old glass ones that were different inside... not really clear. They were (or some were) slow blow fuses. Could take a quick draw without blowing. Maybe something like that would help.

[lowbucktrucks]

Don't use 40a fuse unless the wire is 8AWG. If the wire is 10 gauge use no more than 30a.
Fuse is always sized to wire or wire becomes fuse. This is how you start an electrical fire.
Also, the second 30a fuse between terminal 87 and fan is not needed, the first fuse protects the entire circuit.
If i did not have a clamp meter to determine amps, i would try to borrow one. If not, first try a quality fuse (not HF). If the fuse still blows, chances are component (fan) is bad, but you may want to unplug fan and retest just to make sure it doesn't blow with fan out of circuit.
You also said it only blew when engine running. I would look closely at power wire to fan, could possibly have rubbed a raw spot and be moving around when running.
Hope this helps.

[dazza]

Originally Posted by lowbucktrucks

Don't use 40a fuse unless the wire is 8AWG. If the wire is 10 gauge use no more than 30a.

yea, it's 10awg

Also, the second 30a fuse between terminal 87 and fan is not needed, the first fuse protects the entire circuit.

yea, it came with a kit some time ago and I just left it in.

If i did not have a clamp meter to determine amps, i would try to borrow one. If not, first try a quality fuse (not HF). If the fuse still blows, chances are component (fan) is bad, but you may want to unplug fan and retest just to make sure it doesn't blow with fan out of circuit.

quality 30A blows but not with engine off in on or acc.

You also said it only blew when engine running. I would look closely at power wire to fan, could possibly have rubbed a raw spot and be moving around when running.
Hope this helps.

about to pull the fan/shroud and wiring back to the relay.

Thanks for the input.

[87Skier]

It sounds like your fan is drawing too much current at start up.

My guess as to why it only blows with the engine running is that you are running a much higher voltage with the engine running. What is the running voltage at the battery? Or, there is something wrong with the fan itself. Not sure if you can find some specs on the fan.

[dazza]

Originally Posted by 87Skier

It sounds like your fan is drawing too much current at start up.

My guess as to why it only blows with the engine running is that you are running a much higher voltage with the engine running. What is the running voltage at the battery? Or, there is something wrong with the fan itself. Not sure if you can find some specs on the fan.

I agree that it is a startup current issue. This is one of the Cherokee (CBG4F250) recall fans($45. a few years ago and now they're $180.! I knew I should have bought a few!). Anyways, have yet to find specs other than it's a 4000cfm fan. I'm seeing 1ohm of resistance, so would that not make it (in theory) a 12amp fan? Of course, who knows what it's pulling at start-up. I heard the Taurus fans jump to above 70, which sounds a bit high but I just don't know.

Tonight I threw in a 30A self-resetting breaker. Went to the store and the temp gauge didn't look as if it went high enough for the fan to kick in and since I had the a/c on I didn't hear it, although before turning it off I realized the fan was on. So I'm going to assume it went on, popped the breaker, and after it reset, started up fine. That may work, but not the solution I'm comfortable with.

Also, I know others here are using this fan and I haven't found any threads with the same issue.

[special-K]

Never put a heavier amp fuse in. You have an issue you need to find

[dazza]

Originally Posted by special-K

You have an issue you need to find

hmmm... sounds like something one of my ex's told me as well!

but definitely going to find the electrical problem, to much work put into this thing to have it melt (although that was what I thought about a few relationships too! hehe)

More research and I have found some posts on Jeep and Dodge forums where others had been blowing 30A fuses with this fan as well. Some say it starts up at 26A and then stays about 18A, others say because it's 4000cfm it's probably pulling more like mid 30's at start-up. Looks like I'll have to get a high amp controller or redo the wiring.

[my67c20]

All the kits that i have seen suggest a 30 amp circuit breaker / resetting breaker after the battery. They trip slower, and are designed to handle the current draw on start-up.

[dazza]

Originally Posted by my67c20

All the kits that i have seen suggest a 30 amp circuit breaker / resetting breaker after the battery. They trip slower, and are designed to handle the current draw on start-up.

By "after the battery" do you mean where my schematic at the start of this thread shows the fuse that is blowing? Because unless I'm reading it wrong, that is where the Derale 30a kit shows. I also have one between the relay and the fan, I think I already had it wired up like that from some previous project so I just left it.

From Derale kit instructions:

[dazza]

hmmm... just looked at the Derale instruction image again and it looks as if the fuse I have that is not blowing is where they show it should be. Maybe I just need to delete the fuse that is blowing?

[my67c20]

yes, the fuse that is blowing, is what i meant. You should have some protection between the battery and the relay, this would be the 30 amp breaker.

[dazza]

The fuse that is blowing is really just protecting the relay at this point and I now have a 40/60A there in place of the 30A.

[my67c20]

you need to put a 30 amp circuit breaker between the battery and the relay. Here is a link to Jegs that outline how things should be done. http://www.jegs.com/InstallationInst.../555-10559.pdf

[sleepertruck72]

Is The relay is a 30A Relay ? Did you try replacing the relay ? I would eliminate that fuse from relay to fan. Did you ohm check the wire with the fuse holder that keeps blowing/melting fuses ?

[cleszkie]

Easy there on Harbor Freight That crap has gotten me through a lot of projects! Is it cheap, yes. Will it last, probably not. Will it get the job done once, most likely. You have to take all their stuff with a grain of salt.

[dazza]

Originally Posted by my67c20

yes, the fuse that is blowing, is what i meant. You should have some protection between the battery and the relay, this would be the 30 amp breaker.

I have a 6-slot fuse block coming off the battery and 4-slot relay box next to that. After I found the first melted fuse I moved the corresponding replay to a different fuse slot which is where it is now, still blows fuses there but the 30A circuit breaker seems to be holding in that fuse slot.

you need to put a 30 amp circuit breaker between the battery and the relay. Here is a link to Jegs that outline how things should be done. http://www.jegs.com/InstallationInst.../555-10559.pdf

That is what is there now and seems to be holding, just not sure if that is the solution. Last night I found other forums in which some people were experiencing the same issue with this fan.

Is The relay is a 30A Relay ? Did you try replacing the relay ? I would eliminate that fuse from relay to fan. Did you ohm check the wire with the fuse holder that keeps blowing/melting fuses ?

Still blows in different slot

[71meangreenc10]

Dazza,

Have you thought about this set up?
http://www.summitracing.com/parts/flx-33054

I use one like this (have to get the part number off it) and I have had no problems. It also lets me add in for AC. I have the jeep fan also on my truck.

Smitty

[dazza]

Originally Posted by 71meangreenc10

Dazza,

Have you thought about this set up?
http://www.summitracing.com/parts/flx-33054

I use one like this (have to get the part number off it) and I have had no problems. It also lets me add in for AC. I have the jeep fan also on my truck.

Smitty

Yea, even though the circuit breaker is holding that was the plan. I was looking at these constant temp controllers earlier today. Have you used this since you installed the Jeep fan or were you having issues as well?

[71meangreenc10]

Originally Posted by dazza

Yea, even though the circuit breaker is holding that was the plan. I was looking at these constant temp controllers earlier today. Have you used this since you installed the Jeep fan or were you having issues as well?

I put this one in from jump street, I thought about the fan surging a while back and I have a big fuse that provides power to the temp controller and it works perfectly. I also have a pusher fan for the AC and it is wired to the controller so when it kicks on, it tells the puller fan (jeep) to come on. System works great in my opinion. I can send you some pics this evening if you like.

Mine has been in for over five years with no problems.

Smitty

[dazza]

Originally Posted by cleszkie

Easy there on Harbor Freight That crap has gotten me through a lot of projects! Is it cheap, yes. Will it last, probably not. Will it get the job done once, most likely. You have to take all their stuff with a grain of salt.

haha... I'm with you for the most part, they usually have the one thing that makes part of a project soooo much easier, although you'll have to buy a new one for the next project. Made to break kind of thing. But, if it's my truck I have to buy for the next project because of something they sold me, there would be no going easy on them. Just wanted to let people know of the possibility and I think they need to at least have some sort of QC before these type of things go out the door.