So these are continuity tests 4, 5, and 6.

4 = Green
5 = Blue
6 = Red (turns to purple when intersects with 5).



First off. I made a mistake on #4. As you can see in the green path, the continuity test relies on relay #3 bridging the connection from left cooling fan connector to the right cooling fan connector. So, please retry #4 as follows:

Insert relay #3 in its socket THEN confirm continuity between side A of the left cooling fan connector and side B of the right cooling fan connector AND the socket for pin 87 for relay #2.

Please reply with revised #4 results.

#6 is very strange to me because #5 and #6 share a ground (see purple highlight above). If you got continuity on #5 to your negative battery terminal from relay #3's pin 87 it should mean #6 should get continuity too from the right fan connector's pin A.
The wire leading from right fan connector's pin A should connect to the wire coming from relay #3 pin 87 then both wires should splice together and hit the same ground location via a ground lug / ring terminal (visualize it at the end of the highlighted purple section above). Don't know what to say about this. The only way I can see this happening is if you don't have a wire connected to the right fan connector's pin A, or it's broken, or not connected to ground.

Lane

 

I swear Lane you spend more time helping people with A/C and electrical than working on your car. :-p

 

lane, the way i have my harness wired right now, is with b10(wire going from b10 to s13, and b9 going to s167)

i will swap the wires back to how you have in the diagram, and report my results, from your latest troubleshooting continuity test.

 

ok, not so good news

i inserted relay into harness 3

still failed continuity test from left cooling fan connector "A" to right cooling fan connector "B"

passed continuity from left cooling fan "A" to relay 3 pin wire 30

failed from left cooling fan "A" to relay 3 pin wire 87a
and
from left cooling fan "A" to relay pin wire 87

Note: i am preforming these test on a cold motor, with the key in the off position.

 

don't know if these results matter, since i failed the others,

pass continuity from right fan relay connector "B" to fan 2 relay wire pin 87
and
right fan connector "A" to battery terminal ground.

 

Moving forward, please refer to the relay pins vs the GM notations. I.E., 87, 87a, 20, 85, 86. Since you're building the controller with aftermarket parts they'll just slow us both down as S13 and S167 mean nothing to me and I have to scan the diagram trying to find them

Focus on getting your wiring exactly like the diagram shows. Get yourself to that point, then worry about the continuity tests.

Relay #3 pin 87 MUST connect to the same ground as the right cooling fan connector pin A
Relay #3's pin 87A MUST connect to cooling fan relay #2 pin 87 AND the right cooling fan connector pin B

---------------

New Continuity tests - REMOVE ALL RELAYS:
7. Confirm continuity between right cooling fan connector pin B and the socket for pin 87a for relay 3
8. Confirm continuity between the socket for pin 87 for relay 2 and the socket for pin 87a for relay 3

Excellent. I'd say that almost rules out Relay #2 as the problem as long as your PCM wiring is connected correctly and continuity test #8 above tones out right. To test, install relay #2 in the socket (ONLY relay #2, leave relay #1 and #3 out), then ground the dark blue PCM wire. You should turn on the right cooling fan connector and therefore the fan attached to it. It will be high speed. If it turns on without you grounding the dark blue PCM wire (I.E., the relay clicks as soon as you plug it in and the fan comes on), it means your PCM is ordering on the fan or you have a short in your dark blue wiring somewhere.

This is concerning as it points to 3 possible culprits:

1. The relay is activating as soon as you plug it in (like the dark blue PCM wire is constantly grounded)
2. Bad relay
3. You're reading the writing on your relay incorrectly

SPDT relays are made so that when they are at rest, pins 30 and 87A are connected, or in other words, you should be able to measure continuity between pins 30 and 87A when the relay is unplugged. This is what you should do to verify that #2 is not the problem.

For #1 - Does relay #3 "click" when you plug it in? If the dark blue PCM wire is being shorted to ground it means as soon as you plug in relay #2, your coil activates (clicks) and instead of seeing continuity between 30 and 87a you see continuity between 30 and 87. To rule this out, plug in relay #3 and work from the backside at the socket and measure continuity between 30 and 87 then 30 and 87a then report back which case gets continuity.

Lane

 

Truth. Once you put the information out there and your name gets out it's hard to retire from Q/A.

Lane

 

Also, if you're moving wiring around, that changes your results from the continuity tests, so if you move anything around, you should run through the continuity tests I listed again.

Lane

 

Don't know if there is a "type o" in there, but the diagram shows relay 2 pin 87a, connected to nothing

 

yes relay 3, clicks as soon as i plug it in.
failed continuity from 30 to 87 (relay 3 with relay plugged in)
failed continuity from 30 to 87a (relay 3 with relay plugged in)

 

[QUOTE=HalfSpec;19340076]

first thing i did today was re-check all of the voltage and continuity test(from your earlier post) came back with the same results, that i posted earlier.

 

New Continuity tests - REMOVE ALL RELAYS:
7. Confirm continuity between right cooling fan connector pin B and the socket for pin 87a for relay 3
8. Confirm continuity between the socket for pin 87 for relay 2 and the socket for pin 87a for relay 3


Pass both continuity test

 

Quote:
Originally Posted by atl1234 View Post
pass continuity from right fan relay connector "B" to fan 2 relay wire pin 87
and
right fan connector "A" to battery terminal ground.
Excellent. I'd say that almost rules out Relay #2 as the problem as long as your PCM wiring is connected correctly and continuity test #8 above tones out right. To test, install relay #2 in the socket (ONLY relay #2, leave relay #1 and #3 out), then ground the dark blue PCM wire. You should turn on the right cooling fan connector and therefore the fan attached to it. It will be high speed. If it turns on without you grounding the dark blue PCM wire (I.E., the relay clicks as soon as you plug it in and the fan comes on), it means your PCM is ordering on the fan or you have a short in your dark blue wiring somewhere.


fan relay 2 clicks as soon as i plug it in.

fan will not turn on when adding a jumper wire from negative battery terminal to Dark blue wire pcm

 

Good catch. This should be:

Relay #3's pin 87A MUST connect to cooling fan relay #2 pin 87 AND the right cooling fan connector pin B:

Sorry about that.

Lane

 

This is two confirmations that your dark blue PCM wire is grounded. It's being held to ground which is activating the relays as soon as you plug them in. This is wrong. You should only get a ground on the dark blue PCM wire and activate relay #2 and relay #3 when the PCM orders high speed operation which means it senses your coolant temp is over the high speed setpoint. You've either incorrectly hooked up the dark blue PCM wire or you've kinked the wire / cut the jacket and it's shorted to your chassis somewhere.
Disconnect your PCM wiring and bring it back to the fan controller. Until you've diagnosed your problems, just manually test the fan controller by grounding the dark green wire (low speed) or the dark green and dark blue wire together (high speed). Neither the dark blue or dark green wire should be grounded unless the PCM senses the coolant temp is over its setpoints. In other words, none of your relays should "click" when you plug them in on a cold car.

Lane

 

Very concerning. How about the continuity test on just the removed relay? I.E., remove the relay, hold it in your hand, and use the continuity meter on the relay to measure continuity between 30 and 87 and 30 and 87a.

Report back.

Lane

 

Just to recap all this back and forth, here's what I see as your problems:

1. Based on Continuity test #6 (Confirm continuity between side A of the right cooling connector and Negative Battery Terminal) failing and the fact that FAN #2 didn't come on when you plugged in Relay #2 and it the right fan didn't come on even though the relay clicked means the A side of your right cooling fan connector is not grounded when it should be.

2. At a minimum your dark blue high speed PCM wiring is either shorted to ground/chassis or incorrectly wired to the PCM. I would also check your dark green wire for the same problems. No relays should click when you plug them in on a cold car. If the #1 relay clicks when you put it in it means the dark green wire is shorted / wired incorrect. If relay #2 and #3 click it means your dark blue wire is shorted / wired incorrect.

3. Your relays are either busted or incorrectly wired / labeled. Since they're clicking I doubt they're busted. As I mentioned above. When the SPDT relay is out and in your hand, you'll read continuity between 87a and 30. If it doesn't check your pins / labeling. Hella automotive relays follow the same layout as all general purpose automotive relays:



30 = Left
87A = Center
87 = Right
86 = Top
85 = Bottom

SPDT relay contacts are internally spring loaded to make contact between 30 and 87a at rest / non-powered. If you can't measure continuity between 87a and 30 when the relay is out, something is majorly wrong.

Lane

 

pass continuity on 30 to 87a
fail continuity on 30 to 87

 

yes it is coonnected this way


side not: I'm guessing I'm getting a grounding issue with dark green and dark blue, because i simply tapped those wires, instead of removing them from the original harness..... and repinning the connector with my new wires.

ill report back my findings, if this is my problem from the get go, lane don't kill me, you have taught me a lot, and ill be happy to help the next fool that comes around, so you can retire in peace.

 

ok update;

repinned harness, with no change in the symptoms of how my fans are acting.

texas speed tuned the cpm, there turner set up on low speed fan for 170 degree, 180 degree high speed on

my obd2 reader, reads water temp, and fans are not coming on at 170 degrees or 180 degrees.

if i unplug right fan connector (or relay 3) and re-plug in connector, fan comes on (high speed)

if i unplug high speed fuse, fan goes into low speed.

lane, i disconnected dark blue and dark green wire, and relay 3 and 2 still click when you plug them in. they only stop clicking when i (in addition) remove the purple wire( negative battery terminal to right fan connector "A" and blue wire)

so.... what now?