Hoping someone can shed some light on this. The electric fan in my car quit. I hooked it directly to the battery, to test and it works fine. Checking I find the fuse burnt and the fuse holder melted. Loose connections at the relay, so think that was the problem and will replace fuse holder. There is also a relay, and a adjustable temp controller. All this has worked since before I owned the car, ten years at least. Here's what has me confused. The hot goes to fuse, and then to 86 on relay. There is a jumper from 86 to 30. The two wires from the fan run directly to 85 and 87 on the relay. The adjustable temp controller, has two wires connected to it both go to separate grounds, and of course the sensor in the rad. I don't understand how this works at all, where's the fan ground, why are both wires from fan going to relay? I looked on line and find wiring diagrams and none of them look like that. Can someone shed some light on this, or have I got screwy wiring that somehow has worked for years? Thanks for any help.
This sounds wrong. I should do it like this. Relay 30 hot from fuse, 86 from temp controller, 87 to fan, and 85 to ground. And the fan second wire to ground. And check the turning direction on the fan. Peter
Thanks very much, that sounds much more like I figured it should be wired too. Is there a reason why you say check fan direction, can it turn backwards, and why would it? Thanks again.
Found the wiring diagram for the unit online, slightly different than the ones posted here. Does it look wrong to you guys? Thanks again, am off to tackle it now. https://www.carid.com/images/zirgo/items/pdf/zirzfswak3-installation-instructions.pdf
looks right--it closes the relay by ground to fire the fan-wife's 55 fan wired like that for years with a manual switch and a trinary switch to run fan when ac is on
I wouldn't wire it like that myself, but it will work that way. I've seen relays wired like that. I use term. #85 for ground and term. # 86 for Pos. for the relay coil.
Is an adjustable thermostat really necessary? You could buy a fixed coolant switch for a few bucks that would ground the relay at a fixed temp and open at lower fixed temp. Many temperatures to choose from. Seriously though, how many time does one need to adjust their fan temps? Sent from my iPhone using The H.A.M.B. mobile app
They usually come as a kit so the variable temperature control is used so it can be set as needed. Where it is positioned in the system makes a difference in what the temperature setting needs to be.
Well we have success, just have to tidy a bit now, thanks everyone for all the information and help. John
Yes slightly above operating temperature. Generally Operational temps were at 180 for unpressurized systems and rose to 195 or higher for pressurized radiators.
Should be set to come on about 30 degrees above thermostat opening temperature and off about 15 degrees above thermostat opening temperature. I use 180 degree stat. Fan goes on at 210 and off at 195. Works great. Fan almost never runs unless I'm stopped at light. Fan will lower coolant temp while standing still. Fan goes off when I get rolling. Sent from my LGL158VL using The H.A.M.B. mobile app
#85 and #86 are interchangeable. The coil in the relay is isolated so it really doesn't matter which is positive and which is negative. It's a basic DC electromagnet so will work either way.
Mine comes on at 190, off at 170. So it never runs for long at all. It traffic it will run for maybe 2 or 3 minutes. My t-stat is 180. I used a Spal kit I got on eBay, came with a full install kit. Look around online for their instructions which are very good.
In most cases that is correct. However, some relays have an internal diode to prevent voltage surges when shut off. More for use on vehicles with sensitive electronics on board. On these relays, which look the same from the outside and will plug in to the same socket, term # 85 is to be used as ground. Because all relays aren't created equal, I wire all my relays this way. As stated above, most circuits can be wired either way with no problem.
Thanks for that tidbit, never knew about the diode version. To further confuse the issue I discovered there are both positive and negative terminal #85 versions. https://www.delcity.net/store/Relays-with-Diode/p_73578.h_801565 https://www.delcity.net/store/Relays-with-Diode/p_73578.h_73862
https://m.ebay.com/itm/TYCO-TE-RELAY-V23232-D0001-X001-75-A-AMP-12-V-volt-DC-/352172048270 Best high amp relay I've found.
I was unaware of that pos #85 term. relay. I guess that just means there is never an always or forever. Or never for that matter.
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