Astro Van ABS Light after Blower Resistor Replacement

Problem with my 1999 Chevy Astro Cargo Van Replaced blower motor resistor assembly. Question = The a/c blower motor was working intermittently so I went on line and found most problems were pointing to the blower motor resistor assembly. I replaced this part and it was fine for a few days. Since then it has been an electrical mystery. As it stands, the blower doesn't work most of the time.

Here's the weird part: When I start the van, the ABS light comes on and the fan doesn't work. However, sometimes it starts with the ABS off and then the blower does work, but if you change the fan speed the ABS light comes on and the fan stops working again. Also, the check engine light has come on a number of times but always turns off at some point. By the way, I have actually changed the blower motor resistor twice. When I had the problem initially I don't remember any problems with the dash indicator lights so after I installed the new part and had the problem with the lights I thought the new part was bad so I installed another new one but have the same problem!

Also, when the blower is working you can change the temperature and vent settings without any problems but as soon as you touch the fan speed control the fan stops working and, again, the ABS light comes on. I live in Arizona and need the a/c (by the way, when the blower is working the a/c compressor, etc. works fine) This is driving me nuts, please help. Thanks... Jay P.S. The new part I installed was a different version (supposedly updated)that was bigger. I had no problem cutting the opening and securing it properly.

ANSWER:

WOW, that is weird. OK. First off, a bad resistor usually wont cause an intermittent operation. It usually will cause 1 or more of the speeds to not work at all. Was the resistor a GM factory part? I am wondering that if this part was not correct for your van, if could cause these things. It does not seem likely, but possible. I would re-install the old resistor if you still have it, and see if the ABS light and fan operation are the same as with the new resistor installed.

If no ABS light and fan operating as you described, i would suspect the resistor. If old resistor has no change to the current condition, then i would have to say this is either a faulty fan drawing too much current and you have a couple of wires melted together somewhere causing it to backfeed to the ABS indicator, or a ground problem for the fan. A faulty ground would cause the fan to try to find ground through another circuit, possibly causing the ABS light.

I will send you a few schematics shortly...