ABS gremlin

[stumvr6 0]

Had a search and couldnt hit on anything definitive.

 

Has anyone had an issue with ABS light not lighting when the stereo is powered on initial start up?

 

Recently bought the car and everything works except the stereo which was unplugged at the ISO connectors to the rear of the stereo. They havent been spliced or modified from new. I am working my way through the list of issues still to resolve and this was next on the list.

 

Basically when the ISO connectors are disconnected my ABS light comes on and goes off as it should, however when i plug in the ISO connectors it fails to light at all. I suspect a wiring gremlin behind the fuse box is the issue but before i start buzzing out cables and checking voltages I was wondering if anyone else has seen this?

 

To add to the suspect wiring, the previous owner had a Clifford Alarm removed by an auto electrician as it was faulty. I really think the root cause may lay in there but i have a small glimmer of hope its something more simple....

 

Second issue Is a very intermittent fan. Doesnt work on any setting in general but occasionally kicks in and works on all settings when out driving. Going to check voltages and connections at the switch and resistor pack. Again any advice would be great before the fluke is awoken

[stumvr6 0]

Decided to focus on checking the wiring around the heater fan switch and connector and again at the actual fan connector to see if there was an obvious problem. With all connectors made and the fan speed selector to off, i had a steady 12V at the supply cable terminal of the fan switch connector and 0V at the rest which is a good start! I then selected position 1 on the switch and was getting 12V at all the output terminals of the switch connector... My first thought was that the switch may have failed creating a short, so i decided to unplug the switch from the connector and unplug the fan connector as well to check individually. With a shorting link between supply and position 1, i checked for 12V which was present, however when i checked the pin at the fan connector end it was reading 230mV! Did a continuity check between earth and the fan connector pin for position 1 and it was 0 ohms... Confirmed short circuit!!! I think two or more of the four wires from the fan switch to the motor have fused together or been damaged.

 

Can anyone confirm the routing of these wires if possible? I believe they run from the back of the heater controls up towards the instrument combing past the ABS warning light and then the four settings wires split and go over the top of the heater controls, the glove box and then drop towards the fan?

Can anyone confirm this? Has this happened to anyone else? May have been caused by wites overheating due to the fan bearings wearing out. Any views appreciated. Will keep you all posted on progress

[fendervg 32]

The fan speed fault is common to all VAG cars of that era - it's the resistor in the blower motor in the passenger foot well - it's an easy fix if you can take the unit out and open it up and are handy with electrics, which you seem to be. There's a lot of instructions for it online if you do a search.

 

I'd say you also have a short in the wiring somewhere - best thing to do is to take your time, get a multimeter, loom tape, soldering iron or crimp connectors and some heat shrink wrap and work your way all the way through all the wiring that has been messed with and fix it up and check for good earth and continuity.

[stumvr6 0]

Thanks Fendervg for the advice, managed to trace some broken wires in between the fan switch and the fan. All correctly repaired now. Fan still doesn't work on any setting! I suspect it has may have afailed or there is a loose or dry solder joint. I had a look at the bentley wiring diagram and would i be right in saying the fan should work on position 4 as this enters after the resistors in series on the fan, that is if it was the resistor that had failed? Dont mind soldering and component changing on pcb's, not done it in a long time so the solder will be big!!!

[fendervg 32]

It's usually speed setting 1 that goes first.

[stumvr6 0]

Well it's confirmed I have a dead fan! Removed it and did a direct 12V feed to the fan and nothing!!!! Very high resistance on continuity check as well... Eurocarparts or GSF here I come!!! Thanks for your advice, was helpful in checking in a logical manner. It also give me the opportunity to change the heater control bulb and generally clean it all up.