Problem from the lower temp switch and new harness swap.
Thread Starter
Pro
Joined: Oct 2001
Posts: 554
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From: CA
Problem from the lower temp switch and new harness swap.
Did the lower temperature switch and harness swap tonight. Did the lower thermostat swap a few weeks earlier. Both fans seem to come on at a lower temperature as advertised but I'm not getting a temperature reading from my dash gauge. I didn't touch anything tonight except swapping out the switch, splicing into the relay harness, and adding about 1 1/2 gallons of coolant that I lost when I pulled the old switch. I did a long test drive to get the car up to temperature but the gauge didn't budge. The coolant temperature sensor and harneess are 4 months new and I'm not getting any trouble codes. Any ideas?
Team Owner
Joined: Jan 2003
Posts: 20,333
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From: Summerland B.C. Canada
Re: Problem from the lower temp switch and new harness swap. (gpagaduan)
Not sure about your 90 but my 86 has a temp gauge sending unit on pas. side between #6 and #8. Check for connection there.
Good Luck !!
[Modified by AGENT 86, 5:46 AM 9/8/2003]
Good Luck !!
[Modified by AGENT 86, 5:46 AM 9/8/2003]
Thread Starter
Pro
Joined: Oct 2001
Posts: 554
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From: CA
Re: Problem from the lower temp switch and new harness swap. (AGENT 86)
Ok...now I really need some clarification. I thought between the #6and#8 on the 90 is the switch. Does it also act as the sending unit too? If so, am I supposed to take the original wire and splice into the new harness into for the temp gauge to operate?
Melting Slicks
Joined: May 2000
Posts: 2,029
Likes: 63
Re: Problem from the lower temp switch and new harness swap. (SunCr)
There was special instructions for 90 and 91's only included with my low temp switch. Anyway, in my car (91) there is no switch on the driver side. The hole for the switch is there anyway, it is just plugged.
So, do not touch the temp gauge sender on the passenger side, little late for that though. So, I suggest you return it to the state it was before you started.
Then read the instructions carefully once more. The switch should be installed to the drivers side cylinder head (between #1 and #3 like SunCr said). Then you splice the harness wires to the fan relay wires. The relays are located on the end of the radiator shroud. You should splice one of the harness wires to a relays blue with black or white striped wire and repeat this with the other relay.
If you don't have the instructions contact http://www.madvet.com
Good luck,
ToniH
So, do not touch the temp gauge sender on the passenger side, little late for that though. So, I suggest you return it to the state it was before you started.
Then read the instructions carefully once more. The switch should be installed to the drivers side cylinder head (between #1 and #3 like SunCr said). Then you splice the harness wires to the fan relay wires. The relays are located on the end of the radiator shroud. You should splice one of the harness wires to a relays blue with black or white striped wire and repeat this with the other relay.
If you don't have the instructions contact http://www.madvet.com
Good luck,
ToniH
Thread Starter
Pro
Joined: Oct 2001
Posts: 554
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From: CA
Re: Problem from the lower temp switch and new harness swap. (ToniH)
There was special instructions for 90 and 91's only included with my low temp switch. Anyway, in my car (91) there is no switch on the driver side. The hole for the switch is there anyway, it is just plugged.
[Modified by gpagaduan, 3:19 PM 9/8/2003]
Le Mans Master
Joined: Dec 2000
Posts: 7,839
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From: San Diego, Ca
Re: Problem from the lower temp switch and new harness swap. (gpagaduan)
If you have the dual fans behind the radiator, I'm pretty sure they are controlled by the ECM which grounds the circuit based on inputs from the coolant temp switch (under the throttle body), the a/c pressure switch, and the speedo signal from the VSS. I don't have access to a '90 schematic, but generally, you don't take the ECM out of the picture, you simply splice into the ground side of the fan relay (which is what the ECM controls). Then, the switch you add provides another path to ground when the switch closes. Use the vacant or plugged hole on the driver's side cylinder head for the switch.
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Thread Starter
Pro
Joined: Oct 2001
Posts: 554
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From: CA
Re: Problem from the lower temp switch and new harness swap. (SunCr)
Thanks for the clarification SunCr. That clears up everything. Now, is there a tool to remove the plug or does it just pull out?
Team Owner
Joined: Dec 2000
Posts: 90,675
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From: SE NY
Cruise-In II Veteran
Re: Problem from the lower temp switch and new harness swap. (gpagaduan)
The earlier L98s without the aux fan option also had the aux fan switch hole plugged.
From what I've read here it can be a real issue to remove that plug. I believe several guys have machined a hardened steel stock to fit. If that doesn't work you may need to take it to a shop to have the plug removed and the new switch installed.
From what I've read here it can be a real issue to remove that plug. I believe several guys have machined a hardened steel stock to fit. If that doesn't work you may need to take it to a shop to have the plug removed and the new switch installed.
