2seater Posted January 22, 2023 Share Posted January 22, 2023 (edited) I don't believe brake pads or rotors have any bearing on the ABS light or system. I thought I had a photo of the wiring diagram for the brake pressure switch but can't lay my hand on it at the moment. If memory serves, the red and amber light switching in the pressure switch act pretty much like the two sides of the same relay, one normally closed (red) and the other side (amber)is normally open. That part is independent of the actual pressure switch that controls the pump. The operating pressure is between 2000psi and 2650psi, the lights trigger off somewhere around 1700psi and trigger on at around 1500. You can see that effect when the key is turned on after sitting for a while. Assuming the ABS is otherwise sound, when the pump is running pressurizing the accumulator, the red and amber will be on but when the system reaches the trigger point above, the lights were go off pretty much at the same time. There may be a slight lag on one or the other, but relatively simultaneous. My pump and accumulator test rig has lights connected to check the pressure switch functionality in all phases so the amber light can be triggered through the pressure switch as well. I have never seen a bad one, but I would think it could be checked with a VOM to see if the amber light is because of a defect in the pressure switch. Sorta spitballing here. Edit: I believe the reason for the open switch on the amber light is when it trips, the switch closes and sends power or some indication to the ECBM that the pressure is sufficient. Edited January 22, 2023 by 2seater 2 1 Link to comment Share on other sites More sharing options...
Alchemy333 Posted January 22, 2023 Topic Author Share Posted January 22, 2023 18 hours ago, Ronnie said: The light should blink even if there are no codes stored. No flashes is an indication the EBCM isn't working. Make sure you are shorting the correct terminals and check the ABS fuse under the dash Brake Pump & ABS Fuse Location. Is this what im looking for? Or, what is it and why might it be loose? The pin for the brown/white wire is missing as well. Thanx! Link to comment Share on other sites More sharing options...
Ronnie Posted January 23, 2023 Share Posted January 23, 2023 No, that's not where the ABS fuse is located. I don't know what that blue connector is. Link to comment Share on other sites More sharing options...
Alchemy333 Posted January 23, 2023 Topic Author Share Posted January 23, 2023 @RonnieYah. Posted it in the aaca forum... and came back as radio or CD player... radio currently operates only 1 rear speaker... could be that issue. Not an exciting find... but its found. As far as the ABS im looking into the EBCM availability as a possibility. I guess I'm gonna have to remove the drivers seat to get any real work done now and find those abs fuses... as im not a yoga practitioner. Is it true that the modules are year specific? And that only a part# 1649945 will do the job on my 90? Link to comment Share on other sites More sharing options...
Ronnie Posted January 23, 2023 Share Posted January 23, 2023 26 minutes ago, Alchemy333 said: As far as the ABS im looking into the EBCM availability as a possibility. I guess I'm gonna have to remove the drivers seat to get any real work done now and find those abs fuses... as im not a yoga practitioner. Is it true that the modules are year specific? And that only a part# 1649945 will do the job on my 90? Sorry I can't offer much help. I've not had the pleasure of getting under the dash to find the ABS fuse. I don't know why the EBCM would be different for the '90 model but it might be. 1 Link to comment Share on other sites More sharing options...
2seater Posted January 23, 2023 Share Posted January 23, 2023 Maybe I am in left field but isn’t the ABS fuse above the relays on the firewall in the engine bay, or is there another one? 2 Link to comment Share on other sites More sharing options...
ship Posted January 23, 2023 Share Posted January 23, 2023 21 minutes ago, 2seater said: Maybe I am in left field but isn’t the ABS fuse above the relays on the firewall in the engine bay, or is there another one? I believe you are correct. 1 Link to comment Share on other sites More sharing options...
Ronnie Posted January 24, 2023 Share Posted January 24, 2023 I think you are correct about one for the ABS being above the relays on the firewall (#11 in the photo). According to the '89 FSM there is also one that powers the EBCM in a location that appears to be under the dash (#10 in the photo) and was also reported in the forums years ago. 1990 models might be different. I can't confirm the location of the fuse for the EBCM because I have never laid eyes on it. Just passing on information. 1 Link to comment Share on other sites More sharing options...
Ronnie Posted January 24, 2023 Share Posted January 24, 2023 This is from a post on the other forum that might be helpful. I think it's what I based the How-to guide on that show the location of the EBCM fuse. Quote The ABS light comes on and stays on steady after starting and never goes out. Checked for codes by shorting terminal A to terminal H according to the manual. No codes would flash and the light remained on steady. Th next step is to check the EBCM fuse which is located up under the driver side dash. Not an easy task for an old guy like myself who is not so limber. I had to take the driver seat out. I found the fuse to be blown so naturally changed it and a new fuse also blew (see page 5E1-58). So the next step is to get familiar with the EBCM - Electronic Brake Control Module - in the trunk. Disconnected the control cable and tried a new fuse. The new fuse did not blow and I had power on pin 2 as expected. The fuse blew when I reconnected the control cable and turned on the ignition. Definitely a bad EBCM. With nothing to lose I opened up the EBCM and found a couple melted transistors. End of the road. So now begins a search for a replacement ECBM. I won't say "new" but perhaps unused would be nice. Any tips out there? Thanx Deano 1 Link to comment Share on other sites More sharing options...
Padgett Posted January 24, 2023 Share Posted January 24, 2023 (edited) No flash indicates an issue because a good ebcm will flash "12" if all is good. Edited January 24, 2023 by Padgett 1 Link to comment Share on other sites More sharing options...
2seater Posted January 24, 2023 Share Posted January 24, 2023 Now I remember two different inline fuses under the drivers dash on the 89 we worked on, but I don't know specifically what they were for. We swapped the entire dash with my parts car and lots of things were then right in the open. I have not done anything like that on my 90, so I do not know either 1 1 Link to comment Share on other sites More sharing options...
Alchemy333 Posted February 28, 2023 Topic Author Share Posted February 28, 2023 (edited) So, I got a used EBCM for 60 bucks and I can read codes again. ABS light still on. Codes are 21 and 99. Or 22 and 9+10... cuz the last blink stays lit. No further codes when jumped. Thoughts? I red through past similar posts which appear either non-resolved, or non-conclusive. Thanx! Edited February 28, 2023 by Alchemy333 Link to comment Share on other sites More sharing options...
DAVES89 Posted February 28, 2023 Share Posted February 28, 2023 21 indicates a bad sensor lead. Replace it and most likely the 99 clears up as well. 1 1 Link to comment Share on other sites More sharing options...
Padgett Posted February 28, 2023 Share Posted February 28, 2023 Usually a bad sensor will have missing insulation on the cable and evidence of fraying. I'd inspect all of them. 1 Link to comment Share on other sites More sharing options...
Alchemy333 Posted February 28, 2023 Topic Author Share Posted February 28, 2023 11 hours ago, DAVES89 said: 21 indicates a bad sensor lead. Replace it and most likely the 99 clears up as well. @Padgett I ordered the Saab sensors for mod fit. Should be here Friday. I'll be replacing the struts, harmonic balancer, crank sensor, new sway links at the same time. Ill give an update after I get all that sorted out. 👍 2 Link to comment Share on other sites More sharing options...
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