FAQ
TL;DR: For this XOMAX, the ISO A‑block uses 3 power pins (A8 ground, A4 battery, A7 ACC); “black to A8, yellow to A4, red to A7.” [Elektroda, jdubowski, post #16772595]
Why it matters: Miswired radio-side pins can blow fuses or damage the head unit; this FAQ shows the safe, working pinout and checks for DIY installers.
Quick Facts
- ISO A‑block power map: A8 = ground (black), A4 = +12V battery (yellow), A7 = +12V ACC/ignition (red). [Elektroda, jdubowski, post #16772595]
- Radio-side pins may be shifted from ISO, so colors alone can mislead during installation. [Elektroda, jdubowski, post #16772044]
- Reported failures from a miswire: 20A under-dash fuse and 15A radio fuse both blew. [Elektroda, krzys1221, post #16772638]
- Some “fits many XOMAX models” looms (XM‑DTSB1010) still shorted when connected. [Elektroda, krzys1221, post #16772457]
- XOMAX sets typically include an adapter bundle per the manual; confirm it’s present before wiring. [Elektroda, jdubowski, post #16773273]
How do I wire the ISO power on a XOMAX XM‑2DTSBN62?
Follow the ISO A‑block: A8 ground (black), A4 +12V constant (yellow), A7 +12V ACC/ignition (red). Verify each with a meter before powering. “Black to A8, yellow to A4, red to A7.” [Elektroda, jdubowski, post #16772595]
Why did my 20A and 15A fuses blow after connecting a XOMAX harness?
A miswired loom can short power to the wrong pin, triggering the 20A under‑dash and then the radio’s 15A fuse. Disconnect immediately, confirm A8/A4/A7 with a meter, and inspect the radio loom for swapped positions. [Elektroda, krzys1221, post #16772638]
Are wire colors reliable, or can the radio-side pins be shifted?
Colors often follow ISO, but radio-side pins may be rearranged. If a seller re-pinned the plug, color matching can fail. “It is worse if someone has shifted the cables in the plug from the radio side ...” Always test pins, not colors. [Elektroda, jdubowski, post #16772044]
How do I find ground and power without opening the radio?
Use a multimeter. Find chassis ground first. Confirm A8 is ground, A4 has +12V battery, and A7 has +12V with ignition. “You can find the mass with an ohmmeter even without opening the radio.” [Elektroda, jdubowski, post #16772595]
What is the safest 3-step check before first power-up?
- Meter-check A8 ground continuity to chassis.
- Verify A4 = +12V battery, A7 = +12V ACC.
- Insert correct fuses, then power on. If anything heats, cut power. [Elektroda, jdubowski, post #16772595]
I used the XM‑DTSB1010 “universal” XOMAX loom and got a short. What now?
Stop using that loom. Map each pin against ISO with a meter, then repin or replace the harness. Some “fits many models” looms still short when connected to this radio. [Elektroda, krzys1221, post #16772457]
Could a miswire permanently damage the head unit?
Yes. Feeding +12V into a speaker output or other low-voltage pin can cause internal damage, even if the external fuse blows. “Yeah, especially when you gave +12V to one of the speaker outputs ...” [Elektroda, jdubowski, post #16773273]
My radio had a 15A fuse. Is that the correct value to use after repairs?
Replace like-for-like as labeled on the radio harness or chassis. The case discussed used a 15A radio fuse, which blew during a short. Verify the rating printed on your unit before powering. [Elektroda, krzys1221, post #16772638]
Do XOMAX radios include an adapter bundle from the factory?
They typically ship with an adapter harness per the operating instructions. If yours lacks it, contact the seller or XOMAX support before wiring alternatives. [Elektroda, jdubowski, post #16773273]
I bought the head unit used and got a non-original cube. Any advice?
Do not trust color-to-color with a non-original loom. Meter and repin to ISO A‑block standards, or source the correct bundle. If sold as fitting this model but it doesn’t, raise it with the supplier. [Elektroda, jdubowski, post #16773362]
What does people mean by an ISO “cube” or plug here?
It’s the plastic ISO adapter harness that mates the vehicle wiring to the head unit. In this thread, the OP’s cube had mixed wires, causing shorts. Verify pin positions, not just colors. [Elektroda, krzys1221, post #16771927]
How can I tell if pins are shifted on the radio-side connector?
Visually compare the radio plug to an ISO diagram, then confirm each pin with a meter. If positions differ, depin and move wires to match A8/A4/A7 placement. Colors alone are not sufficient. [Elektroda, jdubowski, post #16772044]
The radio was new and worked before. After a short, is it still worth testing?
Yes, after correcting wiring and replacing fuses, attempt a careful power-up. If no response or distortion occurs, the output stage or protection may be damaged. Proceed only after verifying A‑block pins. [Elektroda, krzys1221, post #16772780]
What is ACC on pin A7?
ACC is the ignition-switched +12V feed that turns the radio on with the key. On this unit, A7 is the ACC input. Confirm with a meter before connection. [Elektroda, jdubowski, post #16772595]
What’s the difference between the car’s under-dash fuse and the radio’s fuse here?
The under-dash 20A protects the vehicle circuit; the 15A on the radio protects the head unit. A hard short can trip both, as reported. Replace fuses only after fixing wiring. [Elektroda, krzys1221, post #16772638]
Should I rely on claims that a loom “fits different XOMAX models”?
Treat such claims cautiously. This case shows a “fits many models” loom still shorted. Always meter-test and verify ISO pin placement before connecting. [Elektroda, krzys1221, post #16772457]
