NO low speed fan signal

[Bills86e]

Engine began to overheat. High speed fan works/comes on when AC button depressed, But the low speed was not comeing on. I discovered that the low
speed of the fan motor was at fault. I replaced and tested before install of
new fan, now both speeds great. Next the thermo switch tested good but the
LS black with green gets no signal at all. HS black with grey works properly
when grounded to the common ground brown wire. I have power at position
30 of the LS relay, and fuse #16 5amp tests good. The harness plug at
the radiator temp switch was heat deteriorating, I think when the LS fan
went South. My problem is I get nothing when I jumper at LS wire at the switch. The plug I removed and just slip the 3 wires on the respective posts.
The wire diagram shows blk-grn wire routed to ECM position 68 (temp signal.
My problem is how to get a signal to LS fan. Any Ideas? Will I need to find
and remove the ECM? Manual ELE-95 shows a wire color change to gry-vio.
ECM between battery & glove box? 2 E-boxes there.

[Bills86e]

My interior guage is idle reading at 1230-1. Can my temp sensor
be cause of no electric in ECM wire to turn on low speed fan?

[Bills86e]

I am thinking........THIS must be the DME signal trigger?
engine coolant temperature sensor? ( on block above oil filter ).
I makes an open & close circuit? Need Electrical help here!

[Bills86e]

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Today, 08:40 AM #61
Bills86e
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Quote:
Originally Posted by JNCoulombe
Since the circuit diagrams that I have seen only show the ECM (DME) as essentially a black box without imput from the ECT it is hard to know how a bad ECT might affect the system. However, jumping between the brn and blk/grn wires at the radiator temperature switch with the ignition switch on will run the low speed fan when the car is cold which suggests that ECT input is not necessary.

Mine when jumping, the the brn and blk/gr at rad does NOT turn fan on, and is my complaint. The fan however does work on both speeds as post 16
proved. I have yet to get voltage thru blk/grn wire.


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Today, 09:58 AM #62
JNCoulombe
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I meant that normally jumping the brn to blk/grn wire will turn on the low speed fan.
Try using a jumper wire from the switch to the relay as I previously suggested. You should at least have a reasonably functional system if that works.

[Bills86e]

How can I get voltage at rad switch blk/grn wire?

[Bills86e]

UPDATE: The Fix, My problem is Solved!
I replaced the engine coolant temperature sensor
My low speed fan now works & cycles correctly
If I now jumper the brown and bleck with green at radiator
coolant switch I gave signal voltage
Thanks to all who helped, Especially COOLJESS76 (he pointed
out the trigger). I am so glad I don't need to replace ECM/DME

[Bills86e]

NOOOOO......only if jumpered. It doesn't cycle when it gets to temp, on its own! Just put a new switch in. 8 burps and not
overheating as of this evening. LS fan STILL fails to come on!
WTF everything is now new.

[cooljess76]

I posted in your other thread, but I myself and I think CirrusSR22 have never seen our low speed fans kick on. There's probably other members that can back me up on this. I'm not sure what the temp or trigger kicks it on though. I know there's a low speed switch(don't know where it's located), but I'd think it's designed to come on at a certain temperature???


Edit; Check your other thread, I think I figured it out!

[tiFreak]

never heard my low speed fan come on either, of course my car only gets up to operating temp while idling since my thermostat's bad, but even then I don't hear it

[Bills86e]

I found this post by Bizar01, Will this be the "fix"?

My fan is now cycling on and off even with the A/C off.

For some reason, the DME (ECM) is preventing my fan to run with the A/C off. I accessed the slow speed relay socket through the bottom of the fuse panel in the engine compartment. I was able to pull it up by unscrewing the 4 torx head screws. I spliced a wire at terminal 85 of the relay and just run it straight to the low temp (80C) contacts of the radiator fan switch. Now the fan runs when called for and stops when no longer needed.

Anyone know if this will work for me?

[JNCoulombe]

Bills86e,
That is essentially what I suggested to you in one of the previous threads. You don't actually have to come up through the bottom of the relay panel. It is quicker and easier (but not quite as neat) to wedge a wire from the top into where the spade from the relay goes. It should work, I ran my car in this configuration for a couple of weeks while I diagnosed my issues.

[Bills86e]

Did you get around to removeing the ECM/DME and opening
it up and see if "contacts" are burned or other?

I am favoring doing the temp wire trick. I never seen ECM,
so inside content could have me bafelled.

Please post your find.

[bazar01]

Originally Posted by JNCoulombe

Bills86e,
That is essentially what I suggested to you in one of the previous threads. You don't actually have to come up through the bottom of the relay panel. It is quicker and easier (but not quite as neat) to wedge a wire from the top into where the spade from the relay goes. It should work, I ran my car in this configuration for a couple of weeks while I diagnosed my issues.

This is true. You don't have to do it the way I did it. I just don't want any wire coming out of the top of the fuse box, but for test purposes, remove the first yellow relay close to the firewall, tap into terminal 85 off the top of the black relay socket by sticking the wire into the female spade then plug the yellow relay back in the socket and this will hold the wire end in place. Use a gauge 18 stranded wire or higher. The coil current draw is <1amp so a small wire gauge will do.
Cut the wire going to the low temp terminal (BW/GRn) of the fan temp switch plug, then solder/splice the other end of the wire from relay terminal 85 to the low temp terminal of the fan temp switch plug.

To test, turn ignition switch to ON, with a jumper wire with aligator clips on both ends, short the low temp terminal of the fan temp switch plug and the brown wire - or any ground closeby. The fan should run in slow speed.

Good luck!

[JNCoulombe]

Bills 86e, I didn't need to open up my DME. My problem ended up being a partially clogged radiator. It flowed well enough to cool the motor as long as I didn't get caught in traffic, but it would not reliably let hot water flow to the temperature sensor. A new radiator fixed my overheating problems. I think in other threads that you stated you had replaced your radiator so that should not be the problem unless you haven't burped it properly.

[bazar01]

Background:
I did this mod due to the failure of the low speed fan from kicking on while idling in my driveway. The car almost overheated but I caught it just before the temp went over half. On the later model cars, aside from the radiator fan switch, the DME also outputs a signal in series with the fan temp switch to turn the radiator fan on. In my case, the DME was not sending an output signal so I had to bypass the DME. On the earlier cars, only the fan temp switch controls the low speed so there is no need to do this bypass.
Based on my observation, the low speed takes quite a while to kick on while idling depending on outside temp. It takes about 5-10 minutes of idling on an 85F outside temp. It maybe shorter above 90F.

First step:
First step is to run a wire from terminal 85 of the low speed relay. This relay is located in the fusebox inside the engine compartment. This is the first yellow relay close to the firewall. I ran the wire from the bottom of the relay socket. The socket can be pulled out from the bottom of the fusebox. The fusebox can be lifted up by removing the 4 torx head screws holding the top of the fusebox. For a reliable splice, solder the connection.