Magown

Rennlisters, it's starting to get rather hot here in the pine straw infested state of Mississippi. So wouldn't you know, my car has started running really warm. Right up to the bottom of the dreaded red line. Only when driving through town and idling. When it's on the highway it cools down to the first line.

I've gone through numerous tests and have determined that there is no power coming from either of the low or high speed terminals in the relay box to the fan wires that connect to the driver side fan. I have tested everything and have narrowed it down to that segment, relay is good and the pass fan works on low and high.

There must be a break in the wire at some point, I was looking for the resistors that make the fans work on low speed. I found some behind the battery under the windshield? Is that the right ones for an air bag car? It was to dark to see the wire colors.

After studying the wiring diagram I think it's safe to say that those resistors will not keep the fan from running on high, maybe low, but not high. I'm probably going to rule them out and just start looking for a problem in the wiring.

Does anyone know the path that the wires travel from the relay box to the fans?

Thanks,

led

Did you check the fuses? Check out <a href="http://www.clarks-garage.com" target="_blank">Clarks Garage</a>, <a href="http://www.clarks-garage.com/shop-manual/cool-01.htm" target="_blank">this page</a> has procedures to troubleshoot the cooling fan system.

Magown

led, if you reread my first post you will notice I said from the low and high speed terminals in the relay box to the fan wiring connector. Let me go into more detail. If I jump 12v to terminals M1 and V1 and the signal is not making it to the fan plug. If I jump 12v to the M2 and V2 the passenger side fan roars to life. See my problem?

Thanks for the reply but I've gone beyond the generic help section. I basically need to know where the wires run so I can find the bad spot.

led

well I'm of no help there, sorry

IceShark

Stephen, did this fan problem pop up after your mechanic did his half-assed job on the headlight wiring kit? If so, I would inspect the harness' where he was monkeying around.

Magown

No, it's been going on since I got the car. At first I bypassed the relay and jumped the pass fan direct to high, it had no problem keeping it cool, I think it running all the time was slowly depleteing my battery.

Waterguy

</font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica"> There must be a break in the wire at some point, I was looking for the resistors that make the fans work on low speed. I found some behind the battery under the windshield? Is that the right ones for an air bag car? It was to dark to see the wire colors. </font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">Yes, those are the resistors for the cooling fans. The wiring diagram shows the wires being red/black and black/red, but on my car they were just red at the resistors. You are right, bad wiring to the resistors would keep the fan from working on low but not on high.

</font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica"> Does anyone know the path that the wires travel from the relay box to the fans?
</font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">According to the wiring diagram, the power from V1 goes from the central electric (relay box) to the resistor, then back to the central electric where it junctions with the power wire straight from from M1. From there it goes from the central electric (junction N22, if it helps) through the "front end wire harness" to the fan. The break must be in the 2.5 sq mm (about 13 guage) red/black wire within this wiring harness, or at the connection with the central electric.

Good luck with it. <img border="0" alt="[thumbsup]" title="" src="graemlins/bigok.gif" />

Magown

Don, I'm still trying to figure out the factory wiring diagram. Where is junction N22?

Thanks,

Waterguy

Stephen, I assume you are referring to the shop manual wiring diagrams, Model 1988 (Volume 5.) I find them confusing as hzll, but the system is described at the start of the wiring diagrams for the 85.5 model (Volume 4), and I quote:

'Each individual wiring diagram shows part of the central-electric box in a dash-dotted frame.

This part of the central-electrics box shows all the lines and relays necessary for the individual wiring diagram.

The 20-pin connectors of the central-electrics box are new. They are clipped together out of five parts.

Part 1, with the moulded-on fastening lug, is the "starting element".

Parts 2, 3 and 4 are "module elements".

Parts 1 to 4 are identified by the numbers 1.....5. [Germans have a funny way of counting. Sounds like King Arthur in Search for the Holy Grail. I assume that means the first four connectors have five pins each.]

Part 5 is a "coding element".' [I have no idea what that means.]

The way I read that, N refers to one of the 20-pin compound plugs that connect to the fuse box, N22 refers to the second wire on the second element of the 20-pin connector (the one after the first one with the moulded-on lug.)

If you look at the wiring diagram for the central electric (1988 model, Sheet 10) you will see that along the left side of the diagram, Connector N, pin 22 is connected on the inside to O33, which is the wire returning from the fan 1 resistor, and to relay G10/M1 (fan relay, pin M1.) On the outside of the box this pin connects to an external "coordinate" B28.

Page 5 of the 1988 wiring diagrams is labelled "Heating, Air Conditioning, Ventilating Coordinates 21-30." This diagram has coordinates A to P across the top and bottom, and 21 to 30 down the sides. If you go to grid B28 (the external coordinate above, which only shows up on Page 5, Coordinates 21 to 30), you see that fan motor 1 gets its power through a red/black wire in the front end wiring harness from terminal N22 on the central electric. You can follow this back and see that power from G10/V1 goes out of the fuse box at pin F22, through passenger compartment wire harness to the 0.9 ohm resistor that you found, back through the same harness into the fuse box at pin O33, joins the wire from G10/M1 which then connects to pin N22.

If you ever really figure this out, make sure you explain it to me. <img border="0" alt="[cherrsagai]" title="" src="graemlins/drink.gif" /> <img border="0" alt="[ouch]" title="" src="graemlins/c.gif" />

tazman

Sorry I don't know about the factory wiring routing and it sounds like you did a good job of checking the relay out. I can't tell from the wording in your post so I just want to make sure you checked to make sure the fan will run if you put 12V to it. Other then that did you test the wire right before the fan connector? The most common place for wires to fail are at the connectors where people pull at them to get the connectors off.

Waterguy

</font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica"> Stephen, did this fan problem pop up after your mechanic did his half-assed job on the headlight wiring kit? If so, I would inspect the harness' where he was monkeying around. </font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">This would be the same front end wiring harness that contains your fan wire. If Tom's ideas don't pan out, it sounds like Iceshark may be onto something.

Magown

Gang, guess what. After all my poking around, I decided to test the fan wiring once again or voltage. Wouldn't you know it, I've now got 12v at the plug and the fan works.

I've had this car since last October, and this is the first time the fan has worked. I guess I will just assume there was a dirty terminal. I hope it's not intermittent. But it could still be a wiring problem. We'll see.

Looks like it will be 85 here today, so I'm going to go sit in traffic and see how it cools.

Thanks for your replies,

Magown

Waterguy, I did pull out the fuse box and look at the all the wiring modules. I removed the two that the fan relay connects to. Looking back, I think that is what made the fan start working again, maybe it wasn't completely seated. Who knows. I'll drive it and see how it performs.

Waterguy

I admire your nerve pulling the fuse box. The pictures I have seen of the wiring to the box scare the crzp out of me, so I am hoping not to have to do that myself. Hope it is a permanent cure.

"Q: Why do the British drink warm beer?
A: Because Lucas also makes refrigerators."