C-4 1986 ECM swap

[John D.]

Any advice on how difficult it is to remove and replace the ECM on a 1986. I have an intermittent fan problem and the service manual seems to point to the ECM as the problem.

I see that TLD has them for $159.00 is that a good source for a replacement or should I go to my GM dealer?

Thanks for the advice, John

[Joe L.]

Re: C-4 1986 ECM swap

John------

The ECM could be the cause of the fan problem or it could be other things. I think that there is a relay and/or another controller in the system for the fans. In any event, I don't think that it is very difficult to change the ECM. Remove the connectors on the back of it and transfer to the new ECM. You may have to transfer the PROM chips from the old to the new unit. For an 86, I think that the ECM is under the right side lower dash. That should be covered in your factory service manual.

TLD is a good place to get the ECM; you won't find a much better price anywhere else. I think that the price is EXCHANGE, though, so you'll have to return the old unit if you want to get the core refund. It's usually substantial on these things----about $100, or more. All of the units on the market, including those from GM and Delco, are re-manufactured units. There is no "NEW" unit avilable anywhere.

[Art B.]

Re: C-4 1986 ECM swap

John:
I had to replace the ECM on my '86 last summer. It is not particularly difficult to do but the area behind the dash on the passenger side is very cramped and it takes a little patience to disconnect the terminals and unscrew the mounting screws. I got my remanufactured ECM from Mid America for about $100 and so far it has worked fine. You have to take out the chip and replace it in the new unit.