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Hey guys another one of those cooling fan questions. I’m kinda stumped here. Also not great when it comes to wiring so be kind. Hah.
So the car has an accel computer installed. I’m wondering if that’s the issue? Not “communicating” maybe?
I’ve had a toggle switch wired in, year ago to have control when temps did get up.
For trouble shooting, so far I’ve ran direct power to each fan (dual set up) to make sure they work. The relay clicks over when the toggle in the car is flipped. I’ve tried grounding the coolant switch to the frame to have the fans come on. Nothing. Tried running ac with car running at temp, and nothing with ac fan, and nothing when up to operating temp.
Where should I go from here to get them running? Ideally I’d like the fans to run automatically like they did from factory, but for now I’d settle for having the toggle run for when temps climb. It makes city driving impossible as is so the car doesn’t get driven like it should.
I have new parts in the garage a switch, Stewart stage 2 water pump, upper and lower hoses, rad cap, flush coolant, and new 195 thermostat when it warms up but without fans it’s all for nothing so I figured I’d tackle this first. Hope someone can help. Thanks.
Last edited by A88GTANotchback; Mar 18, 2018 at 11:02 PM.
i got sick of these issues when i went from computer controlled carb to mechanical and installed a Davies Craig thermatic fan switch and a relay. Surely theres something equivalent in the states. Basically you put a probe somewhere (i wedged mine into the fins of the radiator) wait for it to heat up then use the adjustable **** the set what temp the fans kick in.
I then ran a trigger from the Air conditioning power switch to the trigger on the same relay. When the car gets to a certain temp, the fan kicks in, if the air con is on, the fan kicks in.
These were pretty much a "must have" item on the vast majority of our 80's and early 90's cars here in the 45C+ degree heat. The old school clutch fans had difficulty cooling anything worth a damn, so retrofitting thermofans and these switches was the go.
It looks to be mostly factory on the fan side. But from what I’ve read the relay should be located on the driver side firewall whereas mine is pass front corner where the air filter sits. So I’m assuming it has been modified to some extent.
Well, that'll make it a bit tougher to tell you how to hook it up over the Internet. None of us out here has the slightest idea what's been done to it, so we won't necessarily be able to know what to do next.
It depends on how many relays you have, how many controls from the ECM and whatever else there are, and how the motors are wired to them. With 3 relays and 2 control wires you can have 3 speeds: both motors low speed, one motor high, both motors high. But that will only happen if whatever wiring you have, supports it.
Examine the wiring. (wiring is SO simple...) Should be a big fat red wire with battery on it (hot at all times) going to the relay(s), with a fuse in it perhaps. Should then be a big fat wire, or maybe several such, going to the motor(s), depending on how the system has been modified. Should be a smaller wire with ignition on it (hot in Run only) going to one side of the coil(s), and another small wire(s) going to the other side of the coil(s). You could have it so that the ECM commands some of the lower speed situations and the temp switch in the head puts both motors high. Or any number of other disciplines. All depends on how many relays you have, how many fan motors, how it's all wired, and now many output ports your ECM has available.
In NO case would I want to set it up so that the ONLY way it works, is a toggle switch. The human is the LEAST reliable of all the parts in any given system. Designing it so that disaster strikes if the human efffffs up is a GUARANTEEED FAIL.
Ok guys, I understand wiring is easy to some. But not this guy. I’m doing. What I can buy could use some more advice
I tested voltage at both relays and I get 12 at the tan and the green. From my understanding orange should have the 12 no?
So I jumpered the relay at the black and red wire and tan and can engage the fans for each relay. Black and red to orange has nothing. So digging a little further I pulled the connection in the harness apart and found it has melted the harness connection at the black and red and the ground. Also in the harness connection the wires are mismatched to each side. With the gray wire on relay side not attached to anything at all. Which ever shop did this left me with a lot of headaches. I’m trying to start doing what I can myself to eliminate further hacking. Hope you guys can help me a little to get this figured.
OK so that connector is obviously fornicated. Change it out. You can use ordinary slide terminals, but make sure the ones for the thick wires are the BIG FAT THICK HEAVY-DUTY yellow kind, not the little itty-bitty weenie ones that are just exactly like the red & blue ones except yellow. You want the BIG FAT THICK ones. Once you get them on there, tape em up good to keep water out.
Show us a photo of the relays, and one of their connectors, up close, showing the wire colors.
Those relays and their wiring look largely factory, with minor exceptions, so that's a good thing, as far as it goes.
After fixing the farkled connector, find where the light green wire goes. Somehow that splice doesn't look factory and may be The Clue to whatever mods whoever applied to whatever. Might in fact be the wire to the toggle switch, which once you get the rest of it working right, you can dispense with. After all there's about like a billion cars on the road with electric fans and without toggle switches, that all seem to work just fine. Yours should be just like all those once you fix whatever convinced some backyard shadetree genius that s/he knew more about that sort of thing than all the automotive engineers in the world put together in spite of the fact that s/he couldn't find some simple electrical malfunction.
Alright I just got back from getting the connectors with built in heat shrink. I guess I will leave the green on the fan side out for now since it’s not connected currently.
It should work better; whether completely right or not, we'll see. See what that did, then we can take the next step.
It's not impossible that the toggle switch was somebody's idea of how to fix a motor that was completely disabled by that burnt connector. No idea. I gave up a long time ago trying to retrace the "thought" (I use the word loosely) paths of ... humans. A highly illogical species. Fascinating creatures, but, ...
Well I made the connections. Left the gray and the green out of it, nothing working. Including the toggle. Relay still clicks over. I’m so close to ripping everything out, but then I remember I don’t know how to wire. Haha. Damned if I do damned if I don’t. Should I just buy this and start over? https://www.summitracing.com/parts/prf-30117
Well I ordered a 195 on 185 off kit. My stock relays were clicking but when I tested for power there was nothing once the relay was activated. Also a side note. I was trying to do the parasitic draw test where you disconnect the neg terminal and check amps with everything off. When I touched my meter to make the connection it was clicking over relays, had the interior light on, chiming as if keys were in. Got more then I bargained for with that test. Whole new can of worms to tackle there I guess. Any thoughts?
It's so simple... a relay is just an electrically operated switch. A small amount of power in the coil, controls a much larger amount of power, through the contacts. The coil in those has one connection to ign power at one end, then the ECM, temp switch, toggle, or whatever, grounds the other end to complete the circuit. When the circuit is complete, current flows through the coil, turning it into a magnet; and a small piece of steel near it (the armature), moves toward it due to typical magnetic attraction. That piece of steel has contacts on it which touch when the armature moves, sending power to something else. Really quite simple. You can master this: if someone as dumb as me can do it, then you can too. First thing to do is put all the "hard" and "I'm no good at it" crap out of your head. That just gets in the way.
The orange wires bring power to the relays; the black/red ones take it from there to the motors. The small wires are the coils.
Does the toggle sw make the relay(s) operate? Is there 12V on the orange wires after the relays click on?
I put 12 volts to the relay to activate the switch, but there was no power to the pin when I did this ( put a test light to check). I’m going to start from scratch with the fans, but I’m pretty sure there are more gremlins hiding yet judging by that parasitic test I tried
Well, one thing at a time. Leave the whole parasitic paranoia for later.
I put 12 volts to the relay to activate the switch,
Not sure what that means; doesn't sound like a good idea regardless, since the coils should have 12V on one side when the ign sw is on, and the other side should be grounded by the various control inputs, any/all of which could easily be DESTROYED by connecting hard battery to them. Never a good idea to just go connecting battery to things. Let's hope that didn't happen.
If the relay(s) "click" when they're supposed to, then the coil circuit is working right. Or at least, working right enough that when the relay(s) "click", it should be sending power to the fan(s). That'll be the first thing to establish.
Mentally divide the whole system into 2 halves. First consider the coil (control) half, which includes the ECM, temp switch, toggle switch, whatever that hack job in the harness is, and of course the coils themselves. Next, consider the contact (high-power) half, including the fusible link (if any), big fat orange wire, relay contacts themselves, the black/red wires, that smoked connector you had in your hand up there, and the motors themselves. We're going to figure out which half the bug is in, then divide that half in half and figure out which half it's then in, and so on, until it is unambiguously identified.
Resist the temptation to rewire ANYTHING, install ANYTHING, "jumper" ANYTHING (except for troubleshooting purposes), take out ANYTHING, replace ANYTHING, or otherwise alter ANYTHING about it, until you have determined WHAT IS ACTUALLY BROKEN. That includes the "kit" mentioned above. NO hack jobs, NO further "improvements" let alone "modifications", NO ALTERATION OF ANY KIND until the faulty part (or labor) is rooted out.
First make sure that you can cause the relay(s) to "click" reliably somehow. Whether that is by flipping the toggle switch, unplugging the temp switch in the head and touching the pin on the wire to ground (or using an alligator clip lead to do so), or whatever, make sure you can make the relays "click". Have your assistant do/undo whatever causes this to happen while you listen to them "click" just to be sure.
Is this already known to be the case? have you already done this? if so we can move on. If not, start there.
