BP Posted May 6, 2002 Share Posted May 6, 2002 I have been struggling with my Anti-Lock Brake Light for a couple months now. I thought my last round of trouble shooting linked the Accumulator as the problem. So I ordered a new one from GM Parts Direct and Saturday Night I installed it. <P>After I replaced the Accumulator. The Anti-Lock Light was Out for about 45 minutes!! I was flying high - I was just about ready to declare Victory ...Then outta no-where ... There it was!! I looked down and it was lit!!<P>I checked the ADL by installing the jumper, only code 22 came up (not sure if disconnecting the battery cable might have caused this to come in) but when I drove it to reset it and checked again that was cleared but the Anti-Lock Light was still lit. It been sporadic since.<P> I'm thinking maybe the pressure switch is shutting the pump off before the Anti-Lock Light can clear. But with out a test rig (which I don't have) I'm really grasping at straws<P>Any thoughts? Thanks! Link to comment Share on other sites More sharing options...
Guest wally888 Posted May 6, 2002 Share Posted May 6, 2002 Have you switched or replaced the Relays? Link to comment Share on other sites More sharing options...
padgett Posted May 6, 2002 Share Posted May 6, 2002 If you are talking about the RED light, then the hydraulic boost system is probably at fault however if it is only the YELLOW light then that indicates a failure in the anti-lock electrical system. There should be a trouble code set to say why. <P>I am assuming your jumper on the ALDL was for the brake system (a-g ?) and not the ECM (a-. Link to comment Share on other sites More sharing options...
BP Posted May 7, 2002 Author Share Posted May 7, 2002 Thanks for the rapid responses - Its the Amber Light and NO Codes have ever "set" for as long as I been chasing the problem. All three Relays have been replaced with no affect. <P>Do you know if ABS system for 90 Cadillac Deville is compatible with my 89 Reatta? I have thought about swapping components between them since my Caddi seems to be working OK. I hate to just keeping throwing parts at the problem but the Diagnostic tools are just as expensive at this point as the parts. (Sorry ... just a small meaningless whine from a frustrated Rookie)<P>Thanks a heap for your help<BR>VR<BR>bp Link to comment Share on other sites More sharing options...
Guest wally888 Posted May 7, 2002 Share Posted May 7, 2002 Clarify that you jumped the proper terminals to ck. for Antilock codes? Link to comment Share on other sites More sharing options...
BP Posted May 7, 2002 Author Share Posted May 7, 2002 I double checked my ALDL connection Confirmed pin “A” (top left) to “H” (2nd from bottom on right) still NO Codes yet Amber Anti-Lock Light was always lit. <P>I depressurized (by pumping brake 25 times) and turned key to allow pump to pressurize system 3 times. Amber Anti-Lock Light was always lit. No Codes at ALDL or CRT. <P>thanks again<BR>bp Link to comment Share on other sites More sharing options...
Guest Posted May 7, 2002 Share Posted May 7, 2002 I had this problem when I first bought my Reatta, and had it checked several times by a Buick dealer. They assured me the ABS system was working, but couldn't find the problem.<P>FINALLY, a GoodYear service tech determined that one of the front brake sensors was burned out(?), shorted out(?) -- one of those. Replaced it and I haven't had a problem since! Link to comment Share on other sites More sharing options...
padgett Posted May 7, 2002 Share Posted May 7, 2002 Not home as usual but remember from the fsm that there is a procedure you go through with the ignition key while the ALDL jumper is in place. Not just a matter of jumpering. Link to comment Share on other sites More sharing options...
BP Posted May 7, 2002 Author Share Posted May 7, 2002 padgett <BR>The procedure in the fsm has you turn key to run - this starts pump and pressurizes the system - then install the jumper - then read the 1st code - then remove the jumper and reinstall to read each subsequent code. <P>Initially I thought the problem was electronic but after reviewing the Service Manual It seems an electronic problem would be detected by the ECBM and captured - with NO codes locked in I think the problem is up front with system pressure or switch as it appears these problems are not locked in the ECBM - Also low voltage to ECBM may be a problem too<P>I think I'm stuck unless I can determine what pressure the system is operating I'll have to figure a way to fab up a test rig like the one in the fsm (2000+#'s justs adds some adventure to the process) ... and voltage to the ECBM (low voltage to ECBM may be a problem too) I afraid to troubleshoot the ECBM in case I "Toast" it in the process.<P>Stay tuned ... I shall perservere.<P>Thanks<BR>bp Link to comment Share on other sites More sharing options...
Barney Eaton Posted May 8, 2002 Share Posted May 8, 2002 If it will help.... Tom Jenkins supplied me with an adaptor, as shown in the manual to put between the accumulator and the pump.<P>I have not purchased a gage for several reasons, but I have loaned the adaptor.<P>Because I would like to get it back, the loan is free for the cost of shipping and a deposit that will be returned when the adaptor is returned.<P>If you have access to a gage, I would be happy to put the two together for people to use. We need a hydraulic gage with a high end of 3000, 2500 would probably work.<BR>I have found gages that go to 10k but that makes reading the range we are interested in too difficult. Link to comment Share on other sites More sharing options...
Guest Posted May 8, 2002 Share Posted May 8, 2002 My Grainger Catalog list a 2 1/2" Ametek 3000 PSI pressure gauge with a 1/4" back connection for $17.86. Part # is: 1X535. Link to comment Share on other sites More sharing options...
BP Posted May 8, 2002 Author Share Posted May 8, 2002 Barney - Thanks for the offer of the adaptor.<BR>I just found a new Best Friend at work who offered to fab a a test rig for me. Could supply some ruff dimensions from your test rig. I have the old accummulator to detemine thread size & fit but Rig dimensions would be a perc <P>Thanks again to everyone <P>VR<BR>bp Link to comment Share on other sites More sharing options...
bigrog Posted May 8, 2002 Share Posted May 8, 2002 Check for proper terminal contact at the relay. Sounds like main relay problem, so make sure you have proper terminal tension before you go any further. Most likely situation for a light on with no codes. Link to comment Share on other sites More sharing options...
Guest wally888 Posted May 9, 2002 Share Posted May 9, 2002 As Bigrod said, I would switch relays again. If the Main is bad, as one I had, after switched, it will cause Red light to come on. <BR> Also check for good contact at terminals.<BR> What year is this Reatta?<P> Hope I can explain why I asked the year!<BR> Have been reading my 91 Manual but have never seen a 90 Manual.<BR> Are the code retrieval instructions ( at ALDL) the same for 90 and 91? Both Antilock and other codes?<p>[ 05-08-2002: Message edited by: wally888 ] Link to comment Share on other sites More sharing options...
BP Posted May 9, 2002 Author Share Posted May 9, 2002 I can switch relays around again (Your refering to the relays mounted close to the firewall near the center of the engine compartment ... right?!!<P>I disconnected both last weekend and sprayed both with contact cleaner and reinstalled them<P>I could replace them both too for that matter - I think they were only about $10.00 a piece. <P>Thanks<BR>bp Link to comment Share on other sites More sharing options...
BP Posted May 16, 2002 Author Share Posted May 16, 2002 Barney, In an earlier POST you indicated you had a test rig for testing ABS pressure. <P>Could you tell me the dimensions of the Brake Test Rig you have. Specifically I'm interested in the total length of the tool (not including the accumulator) and the distance from the end of the tool to the gage tap. (doesn't matter which end you measure from as long as you identify which)<P>Also there is a small bit of tube that extends into the end of the accumulator from the connection on the brake housing ... is this to prevent air intrussion into the system when the accumulator is removed?<P>thanks<BR>VR<BR>bp Link to comment Share on other sites More sharing options...
Guest Posted May 22, 2002 Share Posted May 22, 2002 Concerning the red ABS brake lite.........I bought a 1989 Reatta at an auction about 1991...My red brake lite has stayed on constantly.....A service man did tell me that it was probably just a short in the electrical system somewhere and nothing to worry about....( so I don;t ...grin ).....seems there are quite a few electrical problems.....Head lamps are a hassle sometimes to get closed and opened....Light on dash and computer screen at nite will be very bright and won;t dim...sometimes I can turn on my fog lights and this will let me use the adjustor to dim them so that I can see to drive ....Now my computer screen has gone completely dark ...still works but don;t know where to touch the screen to operate anything......but I still love my Reatta... Link to comment Share on other sites More sharing options...
BP Posted May 27, 2002 Author Share Posted May 27, 2002 OK – The saga continues …. I Replaced Both Main and Pump Relays Today with New ones. (Both Old ones tested SAT but none the less 2 NEW have been Installed)<P>Also Today I was bold enough to disconnect the 36 PIN connector on the ECBM and step through the trouble shooting steps in the Service Manual for “ANTI-LOCK LIGHT LIT NO CODES LOCKED IN” (I don't have the special PIN BOX the SM speaks too however i was careful not too cross contacts)<P>Results were as Follows<BR>Step ONE - IGNITION OFF - Measure Resistance PIN 1 to Ground. Results = .2ohms (SAT)<BR>Step TWO -IGNITION ON - Measure VOLTAGE between PIN 1 and PIN 2. Results = 12.5 Volts (SAT)<BR>Step 3 - Measure Resistance PIN 9 to PIN 10. Results = > 5 ohm (Mine was infinite) (UNSAT) SM says - Go to Chart B2. <P>B2 Begins Top Off Reservoir, Disconnect Reservoir Level Switch and measure Resistance PIN A to B. Results = INFINATE … Chart Say REPLACE RESERVOIR! <P>Please! could somebody review and Validate these findings (did I miss a step in the SM somewhere?)… Also What function does PINS C & D perform and LASTLY anyone know the GM part number for the reservoir?<P>god i love this car<P>thanks again<BR>VR<BR>bp Link to comment Share on other sites More sharing options...
padgett Posted May 27, 2002 Share Posted May 27, 2002 Pins 9 and 10 are a very simple circuit - power must come from the ABS computer - is just a loop through a N/C switch in the resovoir (uses a float similar to the gas tank) and through the low pressure switch. <P>Given that you need to have fluid in the resovoir and pressure in the system (key on until red light off, then key off) to have continuity. The manual just says "key off" which could be misleading if the pressure is dissipated.<P>If no continuity (high resistance) in the resovoir level indicator then the circuit will be open.<P>If it were mine and it tested the way you indicate and I knew there was the proper aamount of brake fluid in the resovoir, I would just jumper A & B on the resovoir switch and see if the light goes away (UDA, notary sojak).<P>C&D are on chart 5E1-63 and appear to trigger a "low fluid" warning on the BCM. It is normally open so would not need a jumper.<P>All Reatta TEVES seem to use the same resovoir - 1646522 - which GMPD shows as available (U$92.29 inc S&H) & the switch seems to be glued on so not repairable. Jim Finn may have one also.<P>I do recall a post that mentioned that other resovoirs may be slightly different from the Reatta's & have a clearance problem - anyone recall specifically ? Link to comment Share on other sites More sharing options...
Guest EDBS0 Posted May 27, 2002 Share Posted May 27, 2002 Congratulations padgett you junior member on your 1,000th post!!!!<P>I recall that the reservoir was supplied by Prior on one of their remanufactured units. There was a question about how to clean the old one before it was swapped out.<P>SEE... <A HREF="http://www.aaca.org/cgi-bin/ultimatebb.cgi?ubb=get_topic&f=3&t=002749" TARGET=_blank>http://www.aaca.org/cgi-bin/ultimatebb.cgi?ubb=get_topic&f=3&t=002749</A> Link to comment Share on other sites More sharing options...
BP Posted May 28, 2002 Author Share Posted May 28, 2002 Padgett<P>Thanks for the response to my post and congratulations on your 1,000th post. <P>Sounds like I didn't miss any Service Manual Steps. I did try to jumper the contacts on the switch but I did not get the anticipated response and it was late so I stopped to regroup. <P>I should get my pressure test rig Tuesday (My new best friend was going to re-machine it over the long weekend) Hopefully that will shed more light on the subject.<P>I'm curious about your feedback and your reference to pressure. I'll have to look at the schematics again. these electrical drawings are still confusing to me but I will preservere and figure it out. <P>Another question I had is the ANTI-LOCK DIODE. That was another surprise! Mine looks like a diode crammed into an electrical connector and was wrapped with electrical tape. IS that how its supposed to look? And does it have a GM part number too? <P>thanks again<BR>VR<BR>bob p Link to comment Share on other sites More sharing options...
Guest geokirk Posted May 28, 2002 Share Posted May 28, 2002 Personally, when mine went on I loved it and feel safer too. I hate ABS, but then I know how to stop straight without it too Link to comment Share on other sites More sharing options...
padgett Posted May 28, 2002 Share Posted May 28, 2002 Manual says diode is to protect the computer (line 27) when the mail relay is on (dunno why it would be needed). Suspect an 1N4006 would work just fine.<P>Personally like ABS. Agree an expert with perfect knowlege of both the car and the road (I used to walk the tracks before a race, suprising what you can spot) may be able to stop as well but here in Florida we have what is called "Florida Ice", a noxious mixture of a/c dripping, road oil, and sand that will destroy any semblance of traction. <P>Personally, have had the ABS engage just for a tap or two several times in a hard stop at an intersection.<p>[ 05-28-2002: Message edited by: padgett ] Link to comment Share on other sites More sharing options...
BP Posted June 6, 2002 Author Share Posted June 6, 2002 ANTI_LOCK LIGHT Mystery Solved! Today I continued troubleshooting the AMBER ANTI_LOCK LIGHT problem I have been chasing on & off for months and diagnosed the problem to be with the Reservoir Level Switch. Specifically the A &B Contacts. After the Service Manual Identified the Reservoir Level Switch as a potential problem, As Padget suggested, I installed a jumper across the contacts and continued the diagnosis in the SM. NO other problems were identified. (thank-fully!). <P>I have temporarily left the jumper between the contacts installed until I can get a replacement reservoir & switch. <P>THANK YOU ALL for your patients and support through this endeavor. <P>Now it’s off on the next adventure … “The Chattering Trunk Solenoid”<P>Thanks Again.<BR>VR<BR>bp Link to comment Share on other sites More sharing options...
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