Popping fuses and melting wires

[Bitch'nBronco]

My broncos been possessed with electrical problems. Lately my electric fan has been operating with an electric thermostat triggered at 180* and it runs for a while but then the fuse pops and the ground wire is very hot. I upped the gauge of wire and that doesn't seem to help any. I don't know much about wiring so if this seems ridiculous bear with me. I hooked the fan motor directly to the battery to see if the motor was good (neg to neg post, pos to pos post) and those wires got real hot too. Could this be a ground issue or what? Lost in the sauce, any help would be great. Not fun watching the temp jump up when the fuse pops.

[broncosbybart]

How is it wired? A fan needs to be wired using a relay. The switch (thermostat in your case) isn't designed to have the load for the fan going through it. What size wire is it?

With the ground hooked to the battery, there can't be a grounding issue unless the wire or connection is bad. What size is the fan new or a used junkyard unit?

One way to check it for sure is to wire it directly to the battery and put the mfg recommended or a 20a inline fuse on the hot side. Run the vehicle around town. If the fuse pops, the fan isn't working correctly

[Bitch'nBronco]

Makes sense these are the components:

Fan: Mr. Gasket 1988 http://www.summitracing.com/parts/mrg-1988/overview/
Thermostat: Flexalite 33011 http://www.summitracing.com/parts/flx-33011/overview/

Its fused with a 30A fuze at the fuze box, I'll get an answer as to the gauge of wire. I'm at work and can't remember off hand. I appreciate your help

[Wickedlester]

A bad fan motor can cause a excessive amp draw. That in mind remember that fans pull a constant draw which can sometimes be hard on wiring and connections if they r undersized or commonly today inferior quality. Beware so wire with other metals blended in. Use 100% copper and make certain connections r clean and tight. Also yes u definitely need a relay

[Bitch'nBronco]

Awesome, thanks. So what kind of relay would I need? My connections are just wires soldered together with heat shrink over them. Is there a more preferred method? I never had much luck with the crimp style connectors. I can't speak to the content of the wires themselves, as far as I can tell they're all copper. This is the kit I installed: EZ 21 wiring system http://www.ezwiring.com/wiring_harness.html

[Wickedlester]

Soldered is great. U simply need a standard automotive style 40a spdt found at parts store for around 5 bucks. Not sure I understand what part of that harness u have connected to ur cooling fan. The fan shld be wired directly to the battery w 12awg all copper min via a relay triggered by ur thermostat. There also shld be a fuse at the pos battery connection feeding terminal 30 on the relay. Prewired fan relay harnesses shld be available to simplify things or I can help u with a diagram. If u were closer u cld swing by my shop n I cld help.

[Wickedlester]

Maybe this helps. The relay pictured in bottom left is what u need.

[Bitch'nBronco]

Thats very helpful, I'll give it a shot this weekend. That diagram helps a lot, I definitely don't have a relay for the fan. It just has the fuze going to the fan in the fuze block. I don't know how to better explain it but I'll wire in the relay this weekend and let you know how it goes. Thanks for taking the time to help me out

[snipes243]

Just thought also they do so see full thermostat fan relay kits at advanced auto.

[broncosbybart]

If you have the power for the fan going to the fuse block, that is probably a big part of the problem. As a rule of thumb, you want to keep the wires as short in length as possible. I'd do exactly as Wickedlester suggests with the relay and wiring and mount the relay right up front near the battery and fan. That way you only have a few feet of wire to the relay and then fan. Hope that eliminates all your problems.

Or, just put a mechanical fan on it