Dazed & Confused-I need HELP!

[Schnauzer]

I really need someone to "talk me down". First off I have read every post and comment regarding cooling fans and their circuits. I have good diagnostic skills and perhaps a little better than average electrical skills. I successfully got my son's 79 Spider 2000 cooling fan working properly undoing a PO's creative wiring etc. Now the dilema. I have a 76 Spider with a non op cooling fan. There are six relays at the driver's side inner fender. The plastic mounts for the relay sockets are all broken and thus not fixed into position. The manual diagram of which does what is now a mystery. I started by testing the fan with a 12v source and ground. Fan works. I studied the wiring diagrams and idendified the socket for the fan. This relay is not independent in that it derives its 12v from and through another relay. I checked and cleaned the fuse for the fan and all other fuses. Cleaned the contacts and checked continuity through the fuse block and 12v on either side of the fuses. I checked all of the color coding for the wires that are shown going to these relays. They are in place. I can trigger the switching of the relay with a grounding source bypassing the thermo switch in the radiator. Fan continues not to function. I noticed that there are two types and several variations of relays. All are "WU". Five are five prong, one is four prong. Of the five prong I have been able to clean enough crud off to see a marking of "5K" "5M" "5L". The PO told me he had substituted these relays back and forth between sockets trying to get the fan to work not knowing which one was bad. I have not found a source telling me which relay goes to which socket. One of the sockets is for the electric fuel pump relay. I noticed that when started the motor would run for about 30 seconds then the fuel pump would stop. The relay would then click and the motor would restart immediately. I also found that the relay that effected the charging light in the dash if removed would allow the fuel pump relay to continue to be operational. By Substituting relays in and out I found a combination that allowed the fuel pump to operate correctly and the charge light to function properly. Still cannot get the fan to work. I also bought some 5 prong relays at Napa that appeared to have the proper terminal numbers on them to correspond with the wiring diagrams. Still not working. The questions now are. What relay goes into which socket and why doesn't this demonic fan circuit work. I neared Fiaticide about 1 am this morning. I need help guys.

Jim

[So Cal Mark]

I don't have relay guides here at home, but I''ll respond from work tomorrow and see if we can help sort this out. Not all 5 prong and 4 prong relays can be interchanged though.

[manoa matt]

These pages should help identify the relay locations and the stampings on the relays. If you click on the "all sizes" button above the picture it will be big enough to read.

http://www.flickr.com/photos/bigtimes_fiat/3809372356/
http://www.flickr.com/photos/bigtimes_fiat/3809372370/

I have several relays from a 76 I'm parting out. if you need one let me know the number or location

matt.scarton@gmail.com

[Schnauzer]

Mark & Matt, thanks for your help. I believe I am homing in on the culprit. Emails send to you both. Can't tell you how much I appreciate your respective support.

Jim

[Schnauzer]

I am posting this in hopes that this information might save some of you from going through a week like I have had. My vision has just about returned to normal after studying wiring diagrams for hours and hours. In my trouble shooting effort I had checked voltage and grounds throughout the circuits, through connectors, and at the relay sockets. From the relay sockets forward to the fan motor and horn compressor. I also used jumpers to simulate the action of the relays and create a hard wire switching. Everything checked out at the sockets. Sockets plural because I was checking the horn function also. The switching voltage and current through the relay to the fan comes through the horn socket wiring via the large and small "violet" wires. My mistake was in not checking the voltage under load, ie at the output of the circuit with the relay in place during switching. Turns out that the power supplied to and through the horn relay socket via the "violet" wires comes from and through connector C13. The contacts in this connector were corroded and the current, although measurable at the sockets, did not flow under load when the relay switch accuated. I removed the female contacts from this connector, cleaned, tightened, and replaced them. VIOLA!!!! Everything worked as per design. Bottom line........check, clean, and tighten female terminals in connectors prior to diagnosing a circuit and its components. I think I assumed all along that the relay was bad and hoped my diagnosis would confirm same. It didn't so I questioned my results rather than looking up stream. Hope this is helpful.

Jim

[racydave]

Was'nt a job for just any kind of dog congrats!