relay wiring

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86gnxturbo
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relay wiring

Postby 86gnxturbo » Wed Jul 11, 2007 10:41 pm

Hello All,
I was removing a badly cracked and damaged dash for replacement when I came upon numerous wire in the loom going to the inginition key switch that were cut then just taped back togather. I've done most of the resplicing except one that the Bently manual says goes from x-relay this located on the bottom right corner of the fuse panel and is shown on the diagram on page 6-146. Whomever did the work has tapped in to another hot wire coming from the key and has run this wire to the bk/y wire on the light switch. They went as far as to use solid copper instead of stranded. If you look on page 6-158 and 6-159 you will see the headlight switch , ingnition switch and the relay. Th ebently says the bk/y wire s/b at terminal 86 in the fuse block but mine is at 85 and the br wire is at 86. I'm trying to firure out what this relay is for and how it can be tested. This may be the reason the spliced into another power wire. By the way I did open the harness to find the production splice and it looks ok. The batterys on the meter are no good buy I will try to shoot the cont check tomorrow. This is a 83 caddy diesel. Thanks in advance for your help. :)




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Postby Fatmobile » Thu Jul 12, 2007 2:53 am

You want to know what the x relay is for?
It shuts stuff off while the starter is turning over to reduce current draw by things like front wipers.
While running, it supplys power to the things that shut down when the starter is going around.
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Postby 86gnxturbo » Thu Jul 12, 2007 4:41 am

Can you run a test on it?


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Postby Fatmobile » Fri Jul 13, 2007 12:22 am

Yeah, maybe turn the key on, then turn the front wipers (rear wipers on the Rabbit aren't run through the x relay) on and hit the starter to see if the wipers shut off while the starter is turning.
The heater fan might run through it too.
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Vincent Waldon
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Postby Vincent Waldon » Fri Jul 13, 2007 12:35 am

Although given the wiring the PO did I'm wondering if it was bypassed completely.

If you have the Bentley then you should be able to find the X relay (also called "load reduction relay") and figure out which terminal drives the coil.

Don't have my Bentley handy or I'd look it up for you ... holler if you get stuck.


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Postby 86gnxturbo » Fri Jul 13, 2007 9:18 pm

Ok I have cont between 85 and 86 on the relay so that should be good. When a 12v power source is applied between 30 and 87 on the relay you can hear the relay cycle and then there is no cont between 85 and 86 so that seems to be working well. It seems the relay is in working order. But I have no idea why they spliced into a alternate power for the headlights. Any bright ideas (no pun intended)?



Thanks Glen

coke

Postby coke » Fri Jul 13, 2007 10:29 pm

I find myself doing this at times, because Im not an electrician or a vehicle electrical specialist, but I do know that in the process of troubleshooting, splices get made that don't make sense to eliminate certain possibilities.

I know that doesn't really help you but I think its the most feasible answer.

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Postby 86gnxturbo » Mon Dec 31, 2007 6:09 pm

I know I have not made a post to this topic for some time. But I have a new problem with the wiring the instrument, ashtray, and heater control lights do not come on I have checkedthe fuse, power at the instrument connector and its good. All bulbs are ok. Can anyone tell me what the bulb check relay is used for? I noticed the relay installed is a 4 pin relay vw pn 171937503 and should be a 5 pin. This is the same relay installed in load reduction relay slot. Does anyone know the correct pn for the bulb check relay and what this relays job is? I removed a splice from light switch that ran directly to the inginition nswitch earlier in this post now im wondering if this might have been the story behind that splice. Any input and pn's might be helpful.





Thanks Glen

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bulb check relay

Postby nosparkplugs » Mon Dec 31, 2007 11:09 pm

I am not sure which car you have but if I am reading the circuit diagram I have correctly (81 -84 except Jetta) it supplies ground to most of the indicator lights in the dash when the ignition switch activates the relay through the starting circuit. It does have 5 terminals but I cant tell you what the correct part number is. The following are the pin numbers / functions of the relay. 85 + from start circuit to relay coil, 86 - supply to coil, 30 - to switch, 87 and 86a switched - to the dash lights. This circuit does not supply ground to the wait to start light. It also supplies ground to a few other things. Hope that helps. I can email you copy of the circuit diagram I have if you PM your email address to me.
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light problem

Postby nosparkplugs » Mon Dec 31, 2007 11:50 pm

If your instrument panel lights are still working there is probably a disconnect that is causing the problem. I would look for a grounding problem first. Use a multimeter and do a continuity check to a known good ground. Pull the each bulb first before checking for continuity on the ground side of each bulbs ground. If you still have ground it has to be on the positive side. All of the indicator lights are on one circuit. My book (not as good as the Bently) lists the following on the same circuit; Instrument panel lights, console lights, ashtray light, cigar liter light, radio light, heater control light, rear window defogger light, emergency flasher light.
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Postby Quantum-man » Tue Jan 01, 2008 6:38 am

Sometimes the rheostat on the dimmer switch wears out then instrument lights go off. Try dismantling.
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Postby 86gnxturbo » Tue Jan 01, 2008 11:04 am

Thanks for the help. The car in question is a 83 VW caddy


Thanks Geln
83 VW Caddy

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Postby 86gnxturbo » Tue Jan 01, 2008 6:03 pm

Problem solved headlight switch was bad used one from my donor GTI. Im still working on the issue with the bulb check relay and why the wrong relay is installed. Thanks again for the help.



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83 VW Caddy


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