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Chevy Blazer relays
https://cimg2.ibsrv.net/gimg/blazerf...63eec0c7a0.jpg
https://cimg3.ibsrv.net/gimg/blazerf...5e2cf885f6.jpg I have 1999 RHD Chevy Blazer. I need to identify the electrical relays and confirm the orientation of each one. The photo shows to fuses and relays Everything appears to work except the engine will not start. I now live in France and my friendly garages are frightened of the car!! Thanks for your help |
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George |
Thanks for the info regarding the 1999 Manual - very useful,
What I am looking for is the detail regarding the orientation of the relays. Surely they only locate one way in the socket. Thanks in advance |
Originally Posted by BooTs
(Post 757708)
Thanks for the info regarding the 1999 Manual - very useful,
What I am looking for is the detail regarding the orientation of the relays. Surely they only locate one way in the socket. Thanks in advance Then I looked at the pin-outs of the relays and saw that for the 4-pin ones, the orientation doesn't matter. This was because the paired pins, one set for the coil and one for the switch, are on opposite corners of the rectangular base of the relay. Because it is a rectangle, there are only two orientations possible, 180 degrees from each other. The result is that the paired pins are always in the same opposite corners, e.g., top-left with bottom-right and top-right with bottom-left, no matter which of the two possible orientations is used. The reason this is works is that there is no polarity for these paired pins, i.e., current can flow either direction between them. The orientation of the blades of the pins also enforces the constraint that there are only two possible orientations for inserting the relays. However, I would imagine the engineers used a rectangle base instead of a square because they knew that someone would try to install a square-based relay only 90 degrees off even though the blades of the pins would not be aligned with the receptacle. :) |
Originally Posted by christine_208
(Post 757710)
I have had the same thoughts.
Then I looked at the pin-outs of the relays and saw that for the 4-pin ones, the orientation doesn't matter. This was because the paired pins, one set for the coil and one for the switch, are on opposite corners of the rectangular base of the relay. Because it is a rectangle, there are only two orientations possible, 180 degrees from each other. The result is that the paired pins are always in the same opposite corners, e.g., top-left with bottom-right and top-right with bottom-left, no matter which of the two possible orientations is used. The reason this is works is that there is no polarity for these paired pins, i.e., current can flow either direction between them. The orientation of the blades of the pins also enforces the constraint that there are only two possible orientations for inserting the relays. However, I would imagine the engineers used a rectangle base instead of a square because they knew that someone would try to install a square-based relay only 90 degrees off even though the blades of the pins would not be aligned with the receptacle. :) George |
Thanks guys. I have 2 problems, first - battery drain caused by faulty control unit for ventilation system. Second - after starting to check fuse relays car refuses to start. All instruments , electric windows and door locks, starter motor all work but no ignition????
Any ideas guys Thanks |
You need to check for spark during cranking and if spark is good, do the fuel pressure leak down test.
George |
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