Fan Problem

[HOTSIX]

Guys, I put the car away in the fall after discovering a fan problem and never fixed it.

Ive now taken a few stabs at it and cant figure it out.

I have an 87 ECM with a TT chip and the Ramchargers dual fans. Car ran beautifully all summer for the past 4-5 yrs with that setup. Fan kicked on via the Caspers kit - at 160 deg. Never heated up - ever.

Now I cant find the issue. I replaced the switch that connects to the harness near the PS fender and MAP sensor. Still nothing. I checked the wires going to the connector - 12v power into the switch - no problem there.

The fan works fine - I tried running power to it and both fan motors spin.

It seems that when the car heats up - nothing activates the fan - running power to it from the switch to the fans to kick them on.

The connector has a few (4?) wires running to it.

One of the guys at work has a GN and seemed to think maybe something was wrong with the drivers in the ECM? Ive never heard of this problem.

Like I said - it was working fine then just quit.

Dont know where to turn next....change out coolant temp sensor on top of intake with yellow and blk wires???

 

[BRAD_PADGETT]

Are you running the Caspers 84/85 fan conversion kit with the single relay? Brad

 

[HOTSIX]

Yes....relay.... damn I was calling it a switch haha.

I went to GM and got a replacement relay and that didnt work either....but I still dont know if the relay is bad.

I have no idea how to tell if the CTS is bad...and I dont wanna change it out unless I have to cause it's buried under the FP Reg and some wiring and it'll be a PITA to replace!

I was hoping to just probe the wires of it while running the car to check it forst...if I knew what voltages I was looking for....

 

[BRAD_PADGETT]

I had the same problem with the Caspers 84/85 fan conversion kit with the single relay and the dual ramcharger fans. The dual fans pull can pull too many amps and burn out the single relay. This kit was designed for a single fan. A temporay fix is to put a wire accross the connectors in place of the relay. The fans should turn on when at operating temperature as before.

I fixed the problem permanently by installing the Caspers 86/87 dual fan relay kit after the 84/85 conversion kit. It required a simple rewire of the connectors. I can post PICS if you need them. Brad

 

[HOTSIX]

Brad - pics would be great!

I tried heating up the car several times to see if the ECM is telling the relay to turn on and supply power but it isnt.

A new relay didnt fix it.

The connector has 4 wires
-a black (gnd?)
-a red (12v power all the time)
-a pink (power wire to fan)
-a pink with blk stripe (to ecm I think)

Problem is if I jumper the power to fan (pink) wire it will run at all times (engine off key off) because the battery supplies 12v power to the red wire as soon as the batt is connected.

Think it cud be my chip messing up randomly???

 

[BRAD_PADGETT]

I doubt the chip or the ecm is the problem. My car first blew the relay several month after installing the dual ramchargers on the single relay 84/85 Caspers fan kit. I then ordered another relay from Caspers and it blew out as soon as the fans turned on. I realized the single relay was not enough for the dual ramchargers. I added the 86/87 Caspers fan kit and modified the plug. It goes in between the 84/85 Caspers fan kit and the fans. Picture below. This solution worked for me. I now have a relay on each fan after the relay on the 84/85 fan kit. Brad

 

[HOTSIX]

Guys I'm really stumped by this problem.

I have emailed Caspers and no reply as yet. Also tried TT too to see if he has run into this issue with his chip before or if I have a one off....

I measured the CTS and the voltage decreases as the car heats up so that seems to be working....it goes to 2.45v or so around 160 deg. Still no fan on.

Help!!!! Anyone have any suggestions?

 

[Chatmanboy]

just ran into this problem yesterday... wondering if you firgured out what it is. I contacted casper today about mine to see if they would replace it. I had mine less then a month

 

[6 to go]

My car burned up 1 terminal in the Casper's relay & caused
a similiar proble I was running a single Lincoln fan and
the relay burned out.

 

[Chatmanboy]

exactky the same, thing just looked at it. i have a markVIII fan. was a 100 deg out yesterday. what did you do to fix it? or did you contact caspers?

 

[6 to go]

I called Casper's - "they never heard of a problem like that.
send it back and they will look at it."
I put a new Casper's harness on and a stock 86/87 fan.
Still runs cool. The relay is just too light for anything heavier
than a stock fan, I guess. I didn't try to find a bigger relay.