Hello everybody, I have a question I'm hoping you can help me with. I have a 98 Mustang GT. Completely stock, sorry. The problem I'm having is that the fuel pump will not power up. I traced it and I have no power at the pump, none at the inertia switch, and I don't have anything coming out of the multiple relay box. I'm not sure if that is the right name for it, it is the box that is found inside the passenger fender space. I even replaced it, at the tune of $150, and it didn't help. If somebody out there thinks they can help I can give exact wire numbers that get power and wires that don't. As it stands right now, the only way I can get the car to run is to run a jumper wire (with a fuse, I know, still not a good idea) to I believe wire number 5. That is the wire that comes out of the fuel pump relay, and powers the entire fuel pump circuit. When I do this the car runs fine, I just want to fix this right. Also, I took the car to Autozone to have the codes pulled, I don't know OBD-II, and it spit back no codes. Finally, the night before the problem started, my girlfriend claims she heard a clicking noise that seemed to come from the right rear of the car. I didn't hear it, but I'm not totally discounting it either. As you guys can tell, this is a problem that really has me frustrated. I posted this question to other web forums and got either no answers or really strange ones. I'm hoping you guys can help. If there are any ideas out there and you need me to check anything else, I'm totally game. Any more information you guys need I can supply. I appreciate any help you can give.
98 Mustang Fuel Pump Won't Power Up
- Thread starter ajoyce76
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nyuk98gt
15 Year Member
ajoyce76:
I think you answered your own question: when you bypass the relay, the pump will run. So, the relay has gone bad and needs to be replaced.
If you don't want to spring for a shop manual (+$100), get a Haynes manual (less that $20 at AutoZone); there are wiring diagrams near the back along with lots of other good info.
I think you answered your own question: when you bypass the relay, the pump will run. So, the relay has gone bad and needs to be replaced.
If you don't want to spring for a shop manual (+$100), get a Haynes manual (less that $20 at AutoZone); there are wiring diagrams near the back along with lots of other good info.
nyuk98gt said:
Hey everybody, I'm sorry I took so long to respond. Anyway, it is no the relay. The relay is in the constant control relay box. It has to wires feeding into it. One wire is hot all the time and the other only goes live when the relay needs to click over. The wire that is supposed to be live all the time isn't. I think it's wire number 9. I don't understand what has happened. This occured out of the blue. I have been on every forum, went to allexperts.com, and nothing. Is this such a freakish problem that no one else has had it happen to them. As far as the manuals go, I have a Haynes and a cheapy Chiltons ($20 at Autozone) and both of their wiring diagrams are useless. They only show the diagrams after the CCRM(constant control relay module), and they show the wires going into it, but only so you see their numbers. I think this wire may come right out of the ECM. I can't figure this out. If anybody has any input I would be more than greatful, otherwise I give up.
nyuk98gt
15 Year Member
ajoyce76:
The 'hot at all times' source goes to a fuse panel in the engine compartment, then to the CCRM, and then power is routed to the inertia switch and, finally, to the fuel pump. Since you replaced the CCRM, we will assume it is 'good' and we can rule out the relay.
Dumb question: have you checked/replaced the 20A "fuel pump" fuse in the engine compartment? Is there power (yellow wire) to that panel (on both sides of the fuse)? This is the one that is supposed to be hot at all times.
I do not have a powertrain/electrical shop manual but please post again with progress and we'll see what turns up.
Chris
The 'hot at all times' source goes to a fuse panel in the engine compartment, then to the CCRM, and then power is routed to the inertia switch and, finally, to the fuel pump. Since you replaced the CCRM, we will assume it is 'good' and we can rule out the relay.
Dumb question: have you checked/replaced the 20A "fuel pump" fuse in the engine compartment? Is there power (yellow wire) to that panel (on both sides of the fuse)? This is the one that is supposed to be hot at all times.
I do not have a powertrain/electrical shop manual but please post again with progress and we'll see what turns up.
Chris
nyuk98gt
15 Year Member
ajoyce76:
Another thing to consider is the PATS system. If your 'theft' light is blinking rapidly, then there is a problem with PATS and I think, in that case, your only solution is to head to the dealer (and bring all of your keys).
Chris
Another thing to consider is the PATS system. If your 'theft' light is blinking rapidly, then there is a problem with PATS and I think, in that case, your only solution is to head to the dealer (and bring all of your keys).
Chris
Sam98
Founding Member
There are 2 yellow wires feeding the CCRM (box you replaced). The one going to pin 37 feeds power to the PCM through a relay that is energized by the 12V feeding pin 13 via the red wire with the light green stripe. The PCM power relay also provides the 12V to energize the fuel pump relay which requires a ground from the light blue wire with the orange stripe. The output line to the fuel pump is dark green with a yellow stripe and comes out of pin 5 on the CCRM. The power for the fuel pump comes from a 20A fuse under the hood which goes to the yellow wire at pin 11 of the CCRM. Let me know if you need more information that that... 
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