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Discussion Starter #1
Hi guys,

I have a small technical question that i haven't been able to find the answer to.

Its regarding my cooling fans.

When car is running, both fans come on at same time on low/medium speed. But whenever it goes to high speed my passenger side fan stops but drivers side works normal. Is that normal or do i have a problem some where??
I have the jet 180 installed, and tuned speed to come on at low/high 185/195.
Ac is on!

Anyone noticed something like this before??

Regards
 

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When the fans run, whether low or high speed, both should be operating.
There are three fan relays in the engine compartment fuse box. Identify and test each to verify their functionality.
 

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Discussion Starter #3
When the fans run, whether low or high speed, both should be operating.
There are three fan relays in the engine compartment fuse box. Identify and test each to verify their functionality.
Hi D,

Thanks for your reply. Ill see if i can figure out what relays it is! Why is there 3 relays?? Is it for low/medium/high speed or other reason?
 

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Hi D,

Thanks for your reply. Ill see if i can figure out what relays it is! Why is there 3 relays?? Is it for low/medium/high speed or other reason?
There is no medium speed, just low and high.

Functionally the relays are represented to be:
1) 'Radiator Fan Control' which is supplied with electricity by Fuse #2 rated 40 amps
2) 'Radiator Fan High/Low' which is supplied by Fuse #19 rated 50 amps
3) 'Radiator Fan High' which is also supplied electricity by Fuse #19.

The respective fuse locations should be labeled on the underside of the fuse box cover.

As it was explained to me (I have never verified the explanation) the 'low' speed fan is just both fans operating electrically in series (which splits the voltage equally on both fans so that they run at something like half speed) while the 'high' speed fan is the fans operating electrically in parallel (which applies full voltage to both fans).

Good hunting.
 

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Here you go, you can use this diagram to locate the relays.




Also while there check the condition of the fan blades. The blades are not equally spaced apart and they are known to crack. When that happens should the blades jam onto the shroud at high speed it can be catastrophic for the fan motors because it would then burn out. Best of luck :fing02:

 

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Fan relays electricly put 12 volts in parallel across fan motor for high speed , and electricly put them in series for 6 volts across each at low speed . Both fans should operate wether in series or in parallel voltage . thus low or high speed . There is NO medium speed. TUNERS have that option for med speed but they are not capable of being used on these cars,
 

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What is strange is that for both fans to run at high speed both motors must be good. Then one doesn't run at low speed when they are electrically in series which requires that current flows first through one motor then the other, which wouldn't happen if one was bad.
 

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What is strange is that for both fans to run at high speed both motors must be good. Then one doesn't run at low speed when they are electrically in series which requires that current flows first through one motor then the other, which wouldn't happen if one was bad.
Read the problem again , seems opposite of what you were thinking ,he states low speed, both work (series) but high speed only one works ,(paraellel), makes sense to me, one is not getting 12 v or missing ground connectioin in high speed parallel connection thru the relays
 

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Discussion Starter #9
Hi guys,

Thanks for all your replies. Really appreciate it.

Today i tock some time to watch the fans all the way from engine cold start to fan operation. I seems that first time fans come on, both work.... Then they go to low ops when engine temp is down. But when temp raises again and high speed fan comes on, its only the driver side that goes to high, and passenger side stops completely. Taking a break and letting temp come down again... Its the same. Low and both comes on. High and both comes on first time. Second time only driver side comes on high, and passenger side stops???
I checked the fuses also and all seem fine. Cant really check the relays, So I'm maybe thinking it might be one of them?
Does anyone know if i can switch the relays with some of the other ones in the box to test? Are the relays different?
 

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Relays with same part # and pin configuration are interchageable ,but be careful of what other circuit you will compromise with a bad realay if thats the problem.
 

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Read the problem again , seems opposite of what you were thinking ,he states low speed, both work (series) but high speed only one works ,(paraellel), makes sense to me, one is not getting 12 v or missing ground connectioin in high speed parallel connection thru the relays
My bad. Senior moment!
 

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The three relays involved are identical. The high intensity discharge lamp relay is the same type. With the headlights off you could swap the HID relay into any fan relay position, each inturn, while observing the fan's performance.
 

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Discussion Starter #13
The three relays involved are identical. The high intensity discharge lamp relay is the same type. With the headlights off you could swap the HID relay into any fan relay position, each inturn, while observing the fan's performance.
Thanks DESIREE, ill try that tonight.
 

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What's a good setting high and low a/c on and off w/ a 180 thermo to keep the fans from prematurely burning out?

these are the fan setting i'm going to use. For both A/C on and off.

LS... 194-195 (check after you've set because although you select a whole number it will be something a little different).
MS (even though we don't have one... 197-198
HS... 202-203
 

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What's a good setting high and low a/c on and off w/ a 180 thermo to keep the fans from prematurely burning out?

these are the fan setting i'm going to use. For both A/C on and off.

LS... 194-195 (check after you've set because although you select a whole number it will be something a little different).
MS (even though we don't have one... 197-198
HS... 202-203
Those look much like my numbers, so they should be okay. Let the engine idle and just watch the EVIC for awhile, and listen to the fans
 

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Discussion Starter #16
What's a good setting high and low a/c on and off w/ a 180 thermo to keep the fans from prematurely burning out?

these are the fan setting i'm going to use. For both A/C on and off.

LS... 194-195 (check after you've set because although you select a whole number it will be something a little different).
MS (even though we don't have one... 197-198
HS... 202-203
Looks ok, mine is 192/196/202
 

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Discussion Starter #18
There is no 'med' fan on our cars...med numbers must match hi/lo or the fans can over run and eventually burn out, our not turn on at all... :)

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Hi silver,

Im pretty sure i heard 3 different fan levels when i did the tune... Ut i could be wrong. Ill double check it tomorrow when it gets day time again here.
As of now i ordered 3 new relays as a precaution at the dealer. 60 bucks!!! My god !!

But thanks for the info anyway.... I will re-tune tomorrow.... Maybe thats my issue????
 

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Hi silver,

Im pretty sure i heard 3 different fan levels when i did the tune... Ut i could be wrong. Ill double check it tomorrow when it gets day time again here.
As of now i ordered 3 new relays as a precaution at the dealer. 60 bucks!!! My god !!

But thanks for the info anyway.... I will re-tune tomorrow.... Maybe thats my issue????
You do have three...all Diablo units do... your car only has two! It's part of the software that makes it usable between platforms... you MUST not have three separate temps programmed or else you will have a no high operation...

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Hi silver,

Im pretty sure i heard 3 different fan levels when i did the tune... Ut i could be wrong. Ill double check it tomorrow when it gets day time again here.
As of now i ordered 3 new relays as a precaution at the dealer. 60 bucks!!! My god !!

But thanks for the info anyway.... I will re-tune tomorrow.... Maybe thats my issue????
Again guys try to understand , no med speed is possible, electically fans are low 6v across each series connection , high 12 v across each parallel connectin thru fan relays. Programmers or tuners may have that option for med speed but it it not used in LX cars, no matter what the software says, electrically there are only 2 speeds. Setting the med speed to match the low setting seems the norm for the software to work correctly as others have found out but electrically it only works series-LOW or parrarel-HIGH .
 
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