Resistor wire in cluster harness

Hey guys, I am working on installing an 85 TC full electric cluster in my Ranger but am confused as to what the resistor wire circuit 687(297) and 48 actually do with the cluster.

Here is my reference:
http://rothfam.com/turboranger/tccluster/87tbird2.jpg

I realize that EVTM scan is from the 87, but the cluster setup is the same, I think.

I have the TC cluster pigtail, but only have about 6" of wire. My pigtail has two wires coming out of pin 7, a normal black wire and another black wire with thick insulation and a tiny silver wire, which I assume is the resistor wire.

Can I just install an 8 ohm resistor inline from the key on power and call it good?

Sorry for the long post, thanks for the help.

My complete research of the swap is here:
http://rothfam.com/turboranger/tccluster/

Chris

Chris,

It's part of the IVR system; helps to regulate the voltage powering the instruments.

IMO everyone should ditch it and the crappy mechanical IVR and put an electronic one in; no worries from then on.

Let me know if you need further info. There's a tech article about building an electronic IVR in the tech article section HERE .

HTH.

Thanks for the reply Joe. I wish someone would make these electronic IVRs, I don't feel up to the task to try and build one.

If I put an 8 ohm resistor inline on that part of the circuit, it should do the same function as the resistance wire, correct?

Thanks,
Chris

Replied via email.

Chris, just get a 5 amp regulator chip and make one....... pretty easy to do with your electronic skills. See the tech article I wrote on this..... http://www.turbotbird.com/techinfo/ivr/i...te_IVR.htm

Joe and Jeff have been very helpful in understanding project, thank you. So as I understand it, pin 7 supplies key on power to the stock IVR. From the IVR, 5V goes to the fuel/oil/temp gauges along with the brake indicator and out pin 10 to the low fuel module.

I am not planning to run the low fuel module, so couldn't I build the solid state IVR and supply 5V at pin 10 and eliminate the stock IVR and pin 7, the resistor wire all together?

The diagram here is my reference for the proposed procedure above:
http://rothfam.com/turboranger/tccluster/87tbird2.jpg


Thanks,
Chris

Chris, when I made the solid state IVR for both my Tbirds (86 and 88) the LFW system continued to work as designed. I have sold several SS IVR's to NATO members, and none have reported problems with the LFW. To feed the solid state IVR, I just found a KOER +12 V power source somewhere under the dash, and used that to feed the IVR, completely ignoring the resistance wire in the harness. Since the TC gauges only draw a max of a little under an amp, and the cluster in my 86 draws around 600 mA max, it doesnt really matter where you source the +12 V for the SS IVR from. I did extensive testing with spare clusters to confirm the amp draw under worst case conditions (all gauges pegged at max).

could this IVR be the reason why my oil, temp, and fuel guages aren't working at all??

could this IVR be the reason why my oil, temp, and fuel guages aren't working at all??

It's one possibility

so what are some other ideas on the no gauge problem? i've had the cluster out....nothing outta the ordnary to the nakid eye.